Hypertrophy and fibrosis in the cardiomyopathy of uremia--beyond coronary heart disease

The incidence of hyperkalemia in patients with secondary hyperparathyroidism after ultrasound-guided radiofrequency ablation vs. parathyroidectomy

Introduction

The aim of our study was to compare the incidence of hyperkalemia in maintenance dialysis patients with secondary hyperparathyroidism(SHPT) after parathyroidectomy(PTX) or ultrasound-guided radiofrequency ablation(RFA), and to explore the risk factors and the best preoperative serum potassium threshold.

Methods

We defined hyperkalemia as serum potassium >5.30 mmol/L. Two operation methods were analyzed in subgroups, and the differences in demographic parameters, operation situation and perioperative laboratory indicators were compared between the two groups.

Results

A total of 154 maintenance dialysis patients were included, of which 91 patients received PTX and 63 patients received RFA. 53 patients (34.4%) developed postoperative hyperkalemia. Patients in hyperkalemia group had higher preoperative serum potassium, phosphorus, hemoglobin and 25-hydroxyvitamin D level (p < 0.05). It seemed that males were more prone to suffer hyperkalemia than females, but there was no statistically difference (40.9% vs. 25.8%, p = 0.05). The occurrence of hyperkalemia after the operation was obviously higher in hemodialysis patients. Logistic regression analysis showed that preoperative serum potassium level (OR = 3.269, 95%CI 1.638-6.534, p = 0.001) and PTX (OR = 18.119, 95%CI 5.716-57.438, p < 0.01) were independent risk factors for predicting postoperative hyperkalemia. According to ROC curve analysis, the optimal cutoff value for preoperative serum potassium was 4.66 mmol/L, with a sensitivity of 46.8% and a specificity of 86%.

Conclusion

Hyperkalemia after invasive treatment in patients with severe SHPT was common, and the incidence of hyperkalemia after PTX was significantly higher than that after RFA. Hemodialysis patients were more prone to hyperkalemia, which was related to the preoperative serum potassium level.

Effect of intradialytic exercise training on hemodialysis-induced myocardial stunning: a pilot-controlled trial

Background

Hemodialysis (HD) can lead to left ventricular (LV) transient regional wall motion abnormalities (RWMAs), due to segmental hypoperfusion, better known as myocardial stunning. Repeated episodes of HD-induced ischemia contribute directly to the development of heart failure and increased mortality in patients receiving HD. Intradialytic exercise (IDE) training is capable of exerting favorable effects on the cardiovascular system. However, its impact on HD-induced myocardial stunning remains currently unknown.

Methods

In this prospective controlled study, 31 patients participating in an intradialytic aerobic and resistance training program (3/week for 16 weeks) were compared with 30 patients receiving usual care. Two-dimensional echocardiography was performed at baseline and follow-up both just before HD onset (T0) and at peak stress of HD (Tpeak). LV longitudinal strain from an 18-segment model were used to assess the presence of RWMAs.

Results

Training resulted in a significant reduction of RWMAs at Tpeak between groups [-2.22 segments; 95% confidence interval (CI) -0.49/-3.96; P = .01]. Compared with usual care, trained patients demonstrated also a greater reduction in the decline of global longitudinal strain during HD (-1.45%; 95% CI -0.24/-2.66; P = .01). There were significant reductions in LV mass (-23.3 g; 95% CI -8.7/-37.9; P = .002) and improvements in LV ejection fraction (4%; 95% CI 1.5/6.6; P = .002) between groups favoring IDE. Correlations were found between change in RWMAs with change in LV mass and ejection fraction over the study period.

Conclusion

IDE training is cardioprotective, improving LV remodeling and reducing HD-induced myocardial stunning.

The effects of hemodialysis on the cardiovascular system

Chronic kidney disease and dialysis-dependent end-stage renal disease are increasing in prevalence in the United States. The costs associated with end-stage renal disease management comprise approximately 1% of the federal government's annual budget. Chronic kidney disease and end-stage renal disease cause significant derangements of the cardiac and vascular system. Pathophysiologic hallmarks include alterations of the renin-angiotensin system, chronically increased sympathetic tone, calcium and phosphate imbalance, pro-inflammatory cytokine release, and uremic toxin accumulation. This results in several pathologies specific to the cardiac and vascular systems, which will each be reviewed separately herein.

Identification of Novel Independent Correlations between Cellular Components of the Immune System and Strain-Related Indices of Myocardial Dysfunction in CKD Patients and Kidney Transplant Recipients without Established Cardiovascular Disease

The role of immune system components in the development of myocardial remodeling in chronic kidney disease (CKD) and kidney transplantation remains an open question. Our aim was to investigate the associations between immune cell subpopulations in the circulation of CKD patients and kidney transplant recipients (KTRs) with subclinical indices of myocardial performance. We enrolled 44 CKD patients and 38 KTRs without established cardiovascular disease. A selected panel of immune cells was measured by flow cytometry. Classical and novel strain-related indices of ventricular function were measured by speckle-tracking echocardiography at baseline and following dipyridamole infusion. In CKD patients, the left ventricular (LV) relative wall thickness correlated with the CD14++CD16- monocytes (β = 0.447, p = 0.004), while the CD14++CD16+ monocytes were independent correlates of the global radial strain (β = 0.351, p = 0.04). In KTRs, dipyridamole induced changes in global longitudinal strain correlated with CD14++CD16+ monocytes (β = 0.423, p = 0.009) and CD4+ T-cells (β = 0.403, p = 0.01). LV twist and untwist were independently correlated with the CD8+ T-cells (β = 0.405, p = 0.02 and β = -0.367, p = 0.03, respectively) in CKD patients, whereas the CD14++CD16+ monocytes were independent correlates of LV twist and untwist in KTRs (β = 0.405, p = 0.02 and β = -0.367, p = 0.03, respectively). Immune cell subsets independently correlate with left ventricular strain and torsion-related indices in CKD patients and KTRs without established CVD.

Nonsteroidal Mineralocorticoid Receptor Antagonist Finerenone Improves Diastolic Dysfunction in Preclinical Nondiabetic Chronic Kidney Disease

BACKGROUND

The mineralocorticoid receptor plays a significant role in the development of chronic kidney disease (CKD) and associated cardiovascular complications. Classic steroidal mineralocorticoid receptor antagonists are a therapeutic option, but their use in the clinic is limited due to the associated risk of hyperkalemia in patients with CKD. Finerenone is a nonsteroidal mineralocorticoid receptor antagonist that has been recently investigated in 2 large phase III clinical trials (FIDELIO-DKD [Finerenone in Reducing Kidney Failure and Disease Progression in Diabetic Kidney Disease] and FIGARO-DKD [Finerenone in Reducing Cardiovascular Mortality and Morbidity in Diabetic Kidney Disease]), showing reductions in kidney and cardiovascular outcomes.

METHODS AND RESULTS

We tested whether finerenone improves renal and cardiac function in a preclinical nondiabetic CKD model. Twelve weeks after 5/6 nephrectomy, the rats showed classic signs of CKD characterized by a reduced glomerular filtration rate and increased kidney weight, associated with left ventricular (LV) diastolic dysfunction and decreased LV perfusion. These changes were associated with increased cardiac fibrosis and reduced endothelial nitric oxide synthase activating phosphorylation (ser 1177). Treatment with finerenone prevented LV diastolic dysfunction and increased LV tissue perfusion associated with a reduction in cardiac fibrosis and increased endothelial nitric oxide synthase phosphorylation. Curative treatment with finerenone improves nondiabetic CKD-related LV diastolic function associated with a reduction in cardiac fibrosis and increased cardiac phosphorylated endothelial nitric oxide synthase independently from changes in kidney function. Short-term finerenone treatment decreased LV end-diastolic pressure volume relationship and increased phosphorylated endothelial nitric oxide synthase and nitric oxide synthase activity.

CONCLUSIONS

We showed that the nonsteroidal mineralocorticoid receptor antagonist finerenone reduces renal hypertrophy and albuminuria, attenuates cardiac diastolic dysfunction and cardiac fibrosis, and improves cardiac perfusion in a preclinical nondiabetic CKD model.

Update on Hemodialysis-Induced Multiorgan Ischemia: Brains and Beyond

Hemodialysis is a life-saving treatment for patients with kidney failure. However, patients requiring hemodialysis have a 10-20 times higher risk of cardiovascular morbidity and mortality than that of the general population. Patients encounter complications such as episodic intradialytic hypotension, abnormal perfusion to critical organs (heart, brain, liver, and kidney), and damage to vulnerable vascular beds. Recurrent conventional hemodialysis exposes patients to multiple episodes of circulatory stress, exacerbating and being aggravated by microvascular endothelial dysfunction. This promulgates progressive injury that leads to irreversible multiorgan injury and the well-documented higher incidence of cardiovascular disease and premature death. This review aims to examine the underlying pathophysiology of hemodialysis-related vascular injury and consider a range of therapeutic approaches to improving outcomes set within this evolved rubric.‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬.

Chronic kidney disease associated cardiomyopathy: recent advances and future perspectives

PURPOSE OF REVIEW

Cardiomyopathy in chronic kidney disease (CKD) is a complex condition with multiple triggers and poor prognosis. This review provides an overview of recent advances in CKD-associated cardiomyopathy, with a focus on pathophysiology, newly discovered biomarkers and potential therapeutic targets.

RECENT FINDINGS

CKD is associated with a specific pattern of myocardial hypertrophy and fibrosis, resulting in diastolic and systolic dysfunction, and often triggered by nonatherosclerotic processes. Novel biomarkers, including amino-terminal type III procollagen peptide (PIIINP), carboxy-terminal type I procollagen peptide (PICP), FGF23, marinobufagenin, and several miRNAs, show promise for early detection and risk stratification. Treatment options for CKD-associated cardiomyopathy are limited. Sodium glucose cotransporter-2 inhibitors have been shown to reduce left ventricle hypertrophy and improve ejection fraction in individuals with diabetes and mild CKD, and are currently under investigation for more advanced stages of CKD. In hemodialysis patients calcimimetic etelcalcetide resulted in a significant reduction in left ventricular mass.

SUMMARY

CKD-associated cardiomyopathy is a common and severe complication in CKD. The identification of novel biomarkers may lead to future therapeutic targets. Randomized clinical trials in individuals with more advanced CKD would be well posed to expand treatment options for this debilitating condition.

Phosphate and Coronary Artery Disease in Patients with Chronic Kidney Disease

Cardiovascular disease (CVD) is the leading cause of death in patients with chronic kidney disease (CKD). Both traditional and CKD-related factors are associated with CVD in CKD patients. Traditional factors that play an important role in the atherosclerotic process directly contribute to a higher risk of coronary artery disease in patients with early-stage CKD. Among CKD-related factors, CKD-mineral and bone disorder plays a critical role in the pathomechanism of nonatherosclerotic diseases, which increases the risk of cardiovascular morbidity and mortality in patients with advanced CKD. Higher serum phosphate levels were significantly associated with cardiovascular events and all-cause mortality in patients with or without CKD. An increased phosphate load, directly and indirectly, promotes arterial medial calcification and left ventricular hypertrophy, both of which predispose patients to coronary artery disease. Calciprotein particles that form in a hyperphosphatemic state promote the transformation of vascular smooth muscle cells (VSMCs) into osteoblastic cells, thereby providing a scaffold for medial calcification in the artery. Increases in fibroblast growth factor-23 and disturbed vitamin D metabolism induced by an excessive phosphate load play a significant role in the development of cardiomyocyte hypertrophy and cardiac fibrosis. Recently, hyperphosphatemia was reported to promote de novo cholesterol synthesis in VSMCs and macrophages, which is likely to contribute to statin resistance in patients with end-stage kidney disease. This review outlines the association between increased phosphate load and coronary artery disease in patients with CKD.

Combinative predictive effect of left ventricular mass index, ratio of HDL and CRP for progression of chronic kidney disease in non-dialysis patient

PURPOSE

This current study scrutinized the association among left ventricular mass index (LVMI), ratio of high-density lipoprotein (HDL) and C-reactive protein (CRP), and renal function. Furthermore, we examined the predictive effects of left ventricular mass index and HDL/CRP on progression of non-dialysis chronic kidney disease.

METHODS

We enrolled adult patients with chronic kidney disease (CKD) who were not receiving dialysis and obtained follow-up data on them. We extracted and compared data between different groups. To investigate the relationship between left ventricular mass index (LVMI), high-density lipoprotein (HDL)/C-reactive protein (CRP) levels, and CKD, we employed linear regression analysis, Kaplan-Meier analysis, and Cox proportional hazards regression analysis.

RESULTS

Our study enrolled a total of 2351 patients. Compared with those in the non-progression group, subjects in the CKD progression group had lower ln(HDL/CRP) levels (- 1.56 ± 1.78 vs. - 1.14 ± 1.77, P < 0.001) but higher left ventricular mass index (LVMI) values (115.45 ± 29.8 vs. 102.8 ± 26.31 g/m2, P < 0.001). Moreover, after adjusting for demographic factors, ln(HDL/CRP) was found to be positively associated with estimated glomerular filtration rate (eGFR) (B = 1.18, P < 0.001), while LVMI was negatively associated with eGFR (B = - 0.15, P < 0.001). In the end, we found that both LVH (HR = 1.53, 95% CI 1.15 to 2.05, P = 0.004) and lower ln(HDL/CRP) (HR = 1.46, 95% CI 1.08 to 1.96, P = 0.013) independently predicted CKD progression. Notably, the combined predictive power of these variables was stronger than either variable alone (HR = 1.98, 95% CI 1.5 to 2.62, P < 0.001).

CONCLUSION

Our study findings indicate that in pre-dialysis patients, both HDL/CRP and LVMI are associated with basic renal function and are independently correlated with CKD progression. These variables may serve as predictors for CKD progression, and their combined predictive power is stronger than that of either variable alone.

Cardiovascular changes in the NZB/W F1 mouse model of lupus nephritis

BACKGROUND

Patients with systemic lupus erythematosus (SLE), an autoimmune disease, have a higher risk of cardiovascular (CV) disease and death. In addition, up to 40%-50% of SLE patients develop lupus nephritis (LN) and chronic kidney disease, which is an additional CV risk factor. Thus, the individual contributions of LN and other SLE-specific factors to CV events are unclear.

METHODS

In this study, we investigated the effect of LN on the development of CV changes using the female NZBxNZW F1 (NZB/W) mouse model of lupus-like disease, with female NZW mice as controls. Standard serologic, morphologic, immunohistologic, and molecular analyses were performed. In a separate group of NZB/W mice, systolic blood pressure (BP) was measured during the course of the disease using tail plethysmography.

RESULTS

Our data show marked CV changes in NZB/W mice, i.e., increased heart weight, hypertrophy of the left ventricle (LV) and septum, and increased wall thickness of the intramyocardial arteries and the aorta, which correlated with the progression of renal damage, but not with the age of the mice. In addition, systolic BP was increased in NZB/W mice only when kidney damage progressed and proteinuria was present. Pathway analysis based on gene expression data revealed a significant upregulation of the response to interferon beta in NZB/W mice with moderate kidney injury compared with NZB mice. Furthermore, IFI202b and IL-6 mRNA expression is correlated with CV changes. Multiple linear regression analysis demonstrated serum urea as a surrogate marker of kidney function and IFI202b expression as an independent predictor for LV wall thickness. In addition, deposition of complement factors CFD and C3c in hearts from NZB/W mice was seen, which correlated with the severity of kidney disease.

CONCLUSIONS

Thus, we postulate that the pathogenesis of CV disease in SLE is affected by renal impairment, i.e., LN, but it can also be partly influenced by lupus-specific cardiac expression of pro-inflammatory factors and complement deposition.

Serum and Urine Biomarkers Related to Kidney Fibrosis Predict Kidney Outcome in Czech Patients with IgA Nephropathy

We evaluated biomarkers related to kidney fibrosis for the outcome of patients with IgA nephropathy (IgAN). Clinical parameters (estimated glomerular filtration rate, hypertension, proteinuria) and histological findings were assessed in 134 patients with IgAN at the time of diagnosis and followed up prospectively (mean follow-up time, 56.5 months). We measured biomarkers of collagen and laminin turnover in serum and urine collected at the time of kidney biopsy using a novel enzyme-linked immunosorbent assay. Linear discriminant analysis and logistic regression models were used to predict the patient's kidney outcome. Five serum and urine biomarkers of laminin and collagen turnover (sLG1M, sPRO-C3, sPRO-C6, uPRO-C6/Cr, uC3M/Cr) could significantly differentiae IgAN patients with a worse prognosis. Clinical parameters (glomerular filtration rate (GFR), proteinuria) distinguished patients at risk of IgAN progression with a specificity of 87.3% and a sensitivity of 45.2% (area under the curve-AUC 0.751). The addition of the biomarkers significantly increased the prognostic ability with a specificity of 85.1% and a sensitivity of 73.3% (AUC 0.905). We have identified three serum (sLG1M, sPRO-C3, sPRO-C6) and two urinary markers (uPRO-C6/Cr, u-C3M /Cr) that significantly improve the prognostic ability of markers of kidney function to identify an IgAN patient's risk of progressing to ESKD.

Hypertension and cardiomyopathy associated with chronic kidney disease: epidemiology, pathogenesis and treatment considerations

Chronic kidney disease (CKD) is a complex condition with a prevalence of 10-15% worldwide. An inverse-graded relationship exists between cardiovascular events and mortality with kidney function which is independent of age, sex, and other risk factors. The proportion of deaths due to heart failure and sudden cardiac death increase with progression of chronic kidney disease with relatively fewer deaths from atheromatous, vasculo-occlusive processes. This phenomenon can largely be explained by the increased prevalence of CKD-associated cardiomyopathy with worsening kidney function. The key features of CKD-associated cardiomyopathy are increased left ventricular mass and left ventricular hypertrophy, diastolic and systolic left ventricular dysfunction, and profound cardiac fibrosis on histology. While these features have predominantly been described in patients with advanced kidney disease on dialysis treatment, patients with only mild to moderate renal impairment already exhibit structural and functional changes consistent with CKD-associated cardiomyopathy. In this review we discuss the key drivers of CKD-associated cardiomyopathy and the key role of hypertension in its pathogenesis. We also evaluate existing, as well as developing therapies in the treatment of CKD-associated cardiomyopathy.

Cardiovascular Alterations and Structural Changes in the Setting of Chronic Kidney Disease: a Review of Cardiorenal Syndrome Type 4

Cardiovascular and renal physiology are interrelated. More than a decade ago this was codified in guidelines defining the five subtypes of the cardiorenal syndrome. Morbidity and mortality for those with the cardiorenal syndrome is high compared to demographically matched individuals without cardiorenal disease, acute or chronic. The focus of this review will be the epidemiology, the impact of chronic kidney disease on cardiac structure and function, and associated clinical symptoms, outcomes, and potential treatments for patients with chronic reno-cardiac syndrome, or cardiorenal syndrome type 4. Cardiac structural changes can be profound and are described in detail both at a cellular and physiologic level. Integrating therapies for the treatment of causative or resulting comorbidities may ultimately slow progression of both cardiac and renal disease as well as minimize symptoms and death.

Soluble α-klotho and heparin modulate the pathologic cardiac actions of fibroblast growth factor 23 in chronic kidney disease

Fibroblast growth factor (FGF) 23 is a phosphate-regulating hormone that is elevated in patients with chronic kidney disease and associated with cardiovascular mortality. Experimental studies showed that elevated FGF23 levels induce cardiac hypertrophy by targeting cardiac myocytes via FGF receptor isoform 4 (FGFR4). A recent structural analysis revealed that the complex of FGF23 and FGFR1, the physiologic FGF23 receptor in the kidney, includes soluble α-klotho (klotho) and heparin, which both act as co-factors for FGF23/FGFR1 signaling. Here, we investigated whether soluble klotho, a circulating protein with cardio-protective properties, and heparin, a factor that is routinely infused into patients with kidney failure during the hemodialysis procedure, regulate FGF23/FGFR4 signaling and effects in cardiac myocytes. We developed a plate-based binding assay to quantify affinities of specific FGF23/FGFR interactions and found that soluble klotho and heparin mediate FGF23 binding to distinct FGFR isoforms. Heparin specifically mediated FGF23 binding to FGFR4 and increased FGF23 stimulatory effects on hypertrophic growth and contractility in isolated cardiac myocytes. When repetitively injected into two different mouse models with elevated serum FGF23 levels, heparin aggravated cardiac hypertrophy. We also developed a novel procedure for the synthesis and purification of recombinant soluble klotho, which showed anti-hypertrophic effects in FGF23-treated cardiac myocytes. Thus, soluble klotho and heparin act as independent FGF23 co-receptors with opposite effects on the pathologic actions of FGF23, with soluble klotho reducing and heparin increasing FGF23-induced cardiac hypertrophy. Hence, whether heparin injections during hemodialysis in patients with extremely high serum FGF23 levels contribute to their high rates of cardiovascular events and mortality remains to be studied.

Effect and correlation of patent vascular access flow on left ventricular hypertrophy in kidney transplant patients

Background

Patency of vascular accesses (VA) is associated with left ventricular hypertrophy (LVH) in kidney transplant recipients (KTR). This level of VA flow (VAF) as related to LVH was assessed and an upward level of VA flow recommended for VA closure determined. This recommendation has not been previously reported.

Methods

123 KTR cohort patients were enrolled between August 2016 and December 2017 and their LVH and LV mass index (LVMI) by echocardiography and VAF by Doppler ultrasound were evaluated at baseline and for a 24-month follow-up period. Associations between VAF and LVH were adjusted for other factors.

Results

Patients with patent VA (55.3%) had significantly greater LVH (47.1 vs. 29.1%, an adjusted odds ratio 2.44, p = 0.03) and LVMI (112.15 ± 34.4 vs. 97.55 ± 23.55 g/m², p = 0.009) when compared with the non-VA group. A positive correlation between VAF rate and LVM was noted (r = 0.40, p < 0.001). Subgroup analysis revealed the VAF ≥ 900 ml/min had risks of LVH 3.61, and 2.86 times compared with the non-VA group and the VAF < 900 ml/min group. After a 24-month follow up, there was no significantly individual change in LVMI in patients with or without VA except 6 patients who lost their VA patency during follow-up time had a significant reduction of LVMI (120.17 ± 52.13 to 80.89 ± 22.72 g/m², p = 0.046).

Conclusions

Patency of VA in post-KT patients was associated with LVH. There was a significant reduction of LMVI after loss of VA patency. Patients with stable kidney graft function should be considered for VA closure especially if VAF is ≥ 900 ml/min.

Electrocardiographic parameters of left ventricular hypertrophy and prediction of mortality in hemodialysis patients

BACKGROUND

In hemodialysis patients, left ventricular hypertrophy (LVH) contributes to high cardiovascular mortality. We examined cardiovascular mortality prediction by the recently proposed Peguero-Lo Presti voltage since it identifies more patients with electrocardiographic (ECG) LVH than Cornell or Sokolow-Lyon voltages.

METHODS

A total of 308 patients on hemodialysis underwent 24 h ECG recordings. LVH parameters were measured before and after dialysis. The primary endpoint of cardiovascular mortality was recorded during a median 3-year follow up. Risk prediction was assessed by Cox regression, both unadjusted and adjusted for the Charlson Comorbidity Index and the Cardiovascular Mortality Risk Score.

RESULTS

The Peguero-Lo Presti voltage identified with 21% the most patients with positive LVH criteria. All voltages significantly increased during dialysis. Factors such as ultrafiltration rate, Kt/V, body mass index, sex, and phosphate were the most relevant for these changes. During follow-up, 26 cardiovascular deaths occurred. Post-dialysis Peguero-Lo Presti cut-off as well as the Peguero-Lo Presti and Cornell voltages were independently associated with cardiovascular mortality in unadjusted and adjusted analysis. The Sokolow-Lyon voltage was not significantly associated with mortality. An optimal cut-off for the prediction of cardiovascular mortality was estimated at 1.38 mV for the Peguero-Lo Presti.

CONCLUSIONS

The post-dialysis Peguero-Lo Presti cut-off as well as the Peguero-Lo Presti and Cornell voltages allowed independent risk prediction of cardiovascular mortality in hemodialysis patients. Measuring the ECG LVH parameters after dialysis might allow a standardized interpretation as dialysis-specific factors influence the voltages.

Association between Cardiac Outcomes and Indoxyl Sulfate Levels in Hemodialysis Patients: A Cross-sectional Study

Objective Indoxyl sulfate (IS) is a protein-bound uremic toxin that is associated with cardiovascular events and mortality in hemodialysis (HD) patients. However, the factors affecting the levels of IS are currently unclear. This study aimed to investigate the factors influencing serum IS concentrations in HD patients. Methods We included 100 HD patients from Guangdong Provincial People's Hospital. Baseline characteristics, including sex, age, clinical features, duration of HD, echocardiography findings, electrocardiogram results, and biochemical indicators, were collected and analyzed in relation to serum total-form IS levels. Results Among all 100 patients, serum IS levels were significantly higher in patients aged ≥ 60 years, males, and patients with mitral regurgitation and inadequate dialysis. Among patients aged < 60 years, IS levels were significantly higher among patients with mitral regurgitation compared with those without. Furthermore, multiple linear regression analysis identified sex, age, ventricular septal thickness, and mitral regurgitation as factors independently associated with serum IS (STDβ = -0.475, 0.162, -0.153, 0.142, and 0.136, respectively; all P < 0.05) adjusted for body mass index, smoking, and fasting plasma glucose. Conclusions Male sex, age ≥ 60 years, ventricular septal thickness, and mitral regurgitation are factors associated with high total serum IS concentrations in Chinese HD patients. Elevated IS levels may play a role in the process of mitral regurgitation in HD patients < 60 years old.

Cardiovascular implantable electronic devices in hemodialysis patients: an updated review

Cardiovascular diseases are the leading life-threatening complications in hemodialysis patients. In this scenario, both tachy-arrhythmias and brady-arrhythmias are involved with related hemodialysis and nonhemodialysis-dependent mechanisms; moreover, those arrhythmias usually occur in different time intervals before sudden cardiac death (SCD). Furthermore, current evidence shows that the presence of advanced chronic kidney disease (CKD) reduces the benefits of implantable cardioverter--defibrillators (ICDs), which increases the risk of both arrhythmic and nonarrhythmic death, especially in patients with advanced stages of heart failure. Notably, patients with advanced CKD show a more severe degree of heart failure compared with mild CKD patients. However, the benefits of the ICD implantation in the primary prevention of hemodialysis patients is still controversial, and by now, no significant benefits have emerged compared with nonhemodialysis-dependent CKD patients. In secondary prevention, hemodialysis patients with ICD implantation have higher mortality rates compared with nonhemodialysis-dependent CKD patients with ICD. On the other hand, most articles include hemodialysis patients with reduced left ventricular ejection fraction, neglecting those with preserved systolic function. This review focuses on the epidemiology of SCD in the setting of hemodialysis and the current evidence on ICD implantation in patients on hemodialysis therapy analyzing novel strategies, which might reduce the risk of ICD placing.

Prognostic Implication of Longitudinal Changes in Cardiothoracic Ratio and Aortic Arch Calcification in Hemodialysis Patients

Patients with end-stage renal disease have a high prevalence of cardiovascular disease. Chest radiography can be used to assess cardiothoracic ratio (CTR) and aortic arch calcification (AoAC). The aims of this longitudinal follow-up study were to investigate factors associated with changes in CTR and AoAC and understand whether these changes are associated with overall and cardiovascular mortality in hemodialysis (HD) patients. We enrolled 260 patients undergoing HD who had at least two available chest X-rays from 2008 to 2015. CTR and AoAC were assessed in each patient using measurements from baseline and annual chest X-rays. The CTR increased from 49.05% to 51.86% and the AoAC score increased from 3.84 to 9.73 over 7 years. The estimated slopes were 0.24 (p < 0.0001) for CTR and 0.08 (p = 0.0441) for AoAC. Increased AoAC, older age, female sex, coronary artery disease, and decreased albumin were associated with an increase in CTR, and older age, cerebrovascular disease, decreased albumin, increased Kt/V, and the use of antiplatelet agents were associated with an increase in AoAC. During follow-up, 136 of the 260 (52.3%) patients died, of whom 72 died due to cardiovascular causes. The change in CTR was greater in those who died (p = 0.0125) than in those who survived. The AoAC score was also higher in those who died than in those who survived, although there was no significant difference in the change in AoAC between the two groups (p = 0.8035). CTR and AoAC increased significantly over time in the HD patients in this longitudinal follow-up study, and the change in CTR was greater in those who died than in those who survived. Chest radiography is a simple and useful tool to assess the progression of CTR and AoAC as a prognostic marker.

Comorbidities Associated with One-Year Mortality in Patients with Atrial Fibrillation and Heart Failure

BACKGROUND

Heart failure (HF) and atrial fibrillation (AF) commonly coexist and patients with both diseases have a worse prognosis than those with HF or AF alone. The objective of our study was to identify the factors associated with one-year mortality in patients with HF and AF, depending on the left ventricular ejection fraction (LVEF).

METHODS

We included 727 patients with HF and AF consecutively admitted in a clinical emergency hospital between January 2018 and December 2019. The inclusion criteria were age of more than 18 years, diagnosis of chronic HF and AF (paroxysmal, persistent, permanent), and signed informed consent. The exclusion criteria were the absence of echocardiographic data, a suboptimal ultrasound view, and other cardiac rhythms than AF. The patients were divided into 3 groups: group 1 (337 patients with AF and HF with reduced ejection fraction (HFrEF)), group 2 (112 patients with AF and HF with mid-range ejection fraction (HFmrEF)), and group 3 (278 patients with AF and HF with preserved ejection fraction (HFpEF)).

RESULTS

The one-year mortality rates were 36.49% in group 1, 27.67% in group 2, and 27.69% in group 3. The factors that increased one-year mortality were chronic kidney disease (OR 2.35, 95% CI 1.45-3.83), coronary artery disease (OR 1.67, 95% CI 1.06-2.62), and diabetes (OR 1.66, 95% CI 1.05-2.67) in patients with HFrEF; and hypertension in patients with HFpEF (OR 2.45, 95% CI 1.36-4.39).

CONCLUSIONS

One-year mortality in patients with HF and AF is influenced by different factors, depending on the LVEF.

Cardiovascular Benefits of Extended-Time Nocturnal Hemodialysis

Hemodialysis (HD) remains the most utilized treatment for End-Stage Kidney Disease (ESKD) globally, mainly as conventional HD administered in 4 h sessions thrice weekly. Despite advances in HD delivery, patients with ESKD carry a heavy cardiovascular morbidity and mortality burden. This is associated with cardiac remodeling, left ventricular hypertrophy (LVH), myocardial stunning, hypertension, decreased heart rate variability, sleep apnea, coronary calcification and endothelial dysfunction. Therefore, intensive HD regimens closer to renal physiology were developed. They include longer, more frequent dialysis or both. Among them, Nocturnal Hemodialysis (NHD), carried out at night while asleep, provides efficient dialysis without excessive interference with daily activities. This regimen is closer to the physiology of the native kidneys. By providing increased clearance of small and middle molecular weight molecules, NHD can ameliorate uremic symptoms, control hyperphosphatemia and improve quality of life by allowing a liberal diet and free time during the day. Lastly, it improves reproductive biology leading to successful pregnancies. Conversion from conventional to NHD is followed by improved blood pressure control with fewer medications, regression of LVH, improved LV function, improved sleep apnea, and stabilization of coronary calcifications. These beneficial effects have been associated, among others, with better extracellular fluid volume control, improved endothelial- dependent vasodilation, decreased total peripheral resistance, decreased plasma norepinephrine levels and restoration of heart rate variability. Some of these effects represent improvements in outcomes used as surrogates of hard outcomes related to cardiovascular morbidity and mortality. In this review, we consider the cardiovascular effects of NHD.

Uraemic solutes as therapeutic targets in CKD-associated cardiovascular disease

Chronic kidney disease (CKD) is characterized by the retention of a myriad of solutes termed uraemic (or uremic) toxins, which inflict damage to several organs, including the cardiovascular system. Uraemic toxins can induce hallmarks of cardiovascular disease (CVD), such as atherothrombosis, heart failure, dysrhythmias, vessel calcification and dysregulated angiogenesis. CVD is an important driver of mortality in patients with CKD; however, reliance on conventional approaches to managing CVD risk is insufficient in these patients, underscoring a need to target risk factors that are specific to CKD. Mounting evidence suggests that targeting uraemic toxins and/or pathways induced by uraemic toxins, including tryptophan metabolites and trimethylamine N-oxide (TMAO), can lower the risk of CVD in patients with CKD. Although tangible therapies resulting from our growing knowledge of uraemic toxicity are yet to materialize, a number of pharmacological and non-pharmacological approaches have the potential to abrogate the effects of uraemic toxins, for example, by decreasing the production of uraemic toxins, by modifying metabolic pathways induced by uraemic toxins such as those controlled by aryl hydrocarbon receptor signalling and by augmenting the clearance of uraemic toxins.

Involvement of chronic inflammation via monocyte chemoattractant protein-1 in uraemic cardiomyopathy: a human biopsy study

Aims

Patients undergoing dialysis, even those without coronary artery disease or valvular abnormalities, sometimes present with reduced heart function, which resembles dilated cardiomyopathy (DCM). This condition is known as uraemic cardiomyopathy (UCM). The mechanisms of UCM development are not fully understood. Previous studies demonstrated that the balance between placental growth factor (PlGF) and fms‐like tyrosine kinase‐1 (Flt‐1) is correlated with renal function, and PlGF/Flt‐1 signalling is involved in the development of cardiovascular diseases in patients with chronic kidney disease. This study was conducted to evaluate the pathogenesis of UCM and clarify the differences in the mechanisms of UCM and DCM by using human endomyocardial biopsy and blood samples.

Methods and results

The clinical and pathological features of 30 patients on dialysis with reduced cardiac function [left ventricular ejection fraction (LVEF) ≤50%] (UCM group; mean age: 58.5 ± 9.4 years and LVEF: 39.1 ± 7.2%), 196 DCM patients (DCM group; mean age: 62.7 ± 14.0 years and LVEF: 33.5 ± 8.8%) as controls with reduced cardiac function (LVEF ≤ 45%), and 21 patients as controls with normal cardiac function (control group; mean age: 56.2 ± 19.3 years and LVEF: 67.5 ± 6.7%) were analysed. The percentage of the interstitial fibrosis area in the UCM group was greater than that in the DCM group (P = 0.045). In UCM patients, the percentage of the interstitial fibrosis area was positively correlated with the duration of renal replacement therapy (P < 0.001). The number of infiltrated CD68‐positive macrophages in the myocardium and expression of monocyte chemoattractant protein‐1 (MCP‐1) in cardiomyocytes were significantly greater in the UCM group than in the other groups (P < 0.001, respectively). Furthermore, while the serum level of soluble form of Flt‐1, an endogenous inhibitor of PlGF, in the UCM group was lower compared with that in the DCM group (P < 0.001), the serum levels of PlGF and PlGF/soluble form of Flt‐1 ratio and plasma level of MCP‐1 in the UCM group were higher than those in the DCM group (P < 0.001, respectively).

Conclusions

These results suggest that activated PlGF/Flt‐1 signalling and subsequent macrophage‐mediated chronic non‐infectious inflammation via MCP‐1 in the myocardium are involved in the pathogenesis of UCM.

Myocardial Iron Deficiency Quantification and Effective Cardiac Iron Management Strategy Exploration evaluated by Cardiac T2* Mapping in End-Stage Renal Disease Patients

PURPOSE

To explore myocardial iron content using Cardiac T2* Mapping in dialysis patients undergoing oral iron therapy or intravenous iron supplements compared to healthy controls.

METHODS

Fifty-nine dialysis patients, including 30 peritoneal dialysis (PD) patients who underwent oral iron therapy, 29 hemodialysis (HD) dialysis patients who underwent intravenous iron supplements, and 30 healthy controls were included in the study. Cardiac MRI, including cine, T2 stir, and T2* mapping, was conducted at 3.0T. Quantitive T2* mapping, Cine imaging analysis was performed by two radiologists using cvi42.

RESULTS

The global cardiac T2* value was higher in dialysis patients than in healthy controls (27.1 ± 6.29 ms versus 24.6 ± 3.60 ms, p< 0.05). The global cardiac T2* value of PD patients was higher than that of HD patients (28.5 ± 4.30 ms versus 25.x7 ± 3.54 ms, p< 0.05). The anteroseptal cardiac T2* value was higher in PD patients than in healthy controls (32.0 ± 4.49 ms versus 27.8 ± 4.02 ms, p< 0.05). The global T2* value negatively correlated with left ventricular ejection fraction (LVEF), peak radial strain, circumferential strain, and longitudinal strain.

CONCLUSION

Our study confirmed that PD patients have myocardial iron deficiency despite undergoing oral iron therapy compared to HD patients who received intravenous iron treatments. And the Cardiac T2* value was found to be an independent risk factor and predictor of LVEF and left ventricular altered mechanics. Intravenous iron supplements may be an effective cardiac iron management strategy in patients with HD-dependent end-stage renal disease.

Combination Hydralazine and Isosorbide Dinitrate in Dialysis-Dependent ESRD (HIDE): A Randomized, Placebo-Controlled, Pilot Trial

Background

Combination therapy with isosorbide dinitrate (ISD) and hydralazine (HY) reduces heart failure mortality. The safety and tolerability in individuals requiring maintenance hemodialysis (HD) is unknown.

Methods

Single-center, randomized, placebo-controlled, double-blind pilot trial to explore safety and tolerability of ISD/HY in maintenance HD. Participants were randomized to placebo or combination ISD/HY. Dose was escalated over 3 weeks from ISD 10 mg/HY 10 mg to ISD 40 mg/HY 75 mg three times per day with the maximum tolerated dose maintained for the subsequent 21 weeks. Primary endpoints included adverse events, adverse events precluding further treatment with study medication, serious hypotension (i.e., requiring hospitalization or emergency room visit), and recurrent intra-dialytic hypotension. Efficacy signals included change in mitral annular E' velocity by tissue Doppler echocardiography and change in left ventricular coronary flow reserve on positron emission tomography.

Results

A total of 17 individuals were randomized to ISD/HY (N=7) or placebo (N=10). All participants assigned to ISD/HY completed dose escalation to 40/75 mg, but dose reductions were required in two participants. No participants discontinued therapy. There were no serious hypotension events. Recurrent intradialytic hypotension was less frequent with ISD/HY (0.47 events/patient-year) than placebo (1.83 events/patient-year, P=0.04). In contrast, nausea (ISD/HY, 1.90 events/patient-year; placebo, 0.50 events/patient-year, P=0.03) was significantly more frequent, and headache and diarrhea were numerically but not significantly more frequent with ISD/HY. Adverse events were more frequent with ISD/HY (11.4 events/patient-year) than placebo (6.31 events/patient-year). We did not detect between-group differences in the change in E' (P=0.34); ISD/HY showed a mean increase of 0.6 cm/s (SD 1.1), and placebo showed a mean decrease of 0.04 cm/s (SD 0.9). Changes in coronary flow reserve were minimal, -0.3 (0.2) with ISD/HY and -0.03 (0.5) in the placebo group, P=0.19.

Conclusions

ISD/HY appears to be well tolerated in patients being treated with maintenance HD, but headache and gastrointestinal side effects occur more frequently with ISD/HY compared with placebo.

Coronary microcirculation and left ventricular diastolic function: comparison between patients on hemodialysis and peritoneal dialysis

BACKGROUND

End-stage renal disease is considered to influence coronary microcirculation and left ventricular (LV) diastolic function. We investigated whether differences exist in LV diastolic function indices and coronary flow reserve (CFR) between patients on hemodialysis (HD) and peritoneal dialysis (PD).

METHODS

A complete transthoracic echocardiographic study was performed on 21 HD and 22 PD patients and LV diastolic function was evaluated. CFR was estimated using transthoracic Doppler echocardiography on the left anterior descending artery, during high-dose dypiridamole infusion.

RESULTS

HD and PD groups did not differ regarding Doppler-derived diastolic indices, but they significantly differed in the frequency of severe LV hypertrophy (38.1% in HD vs 4.5% in PD group, p = 0.009) and grade II diastolic dysfunction (42.9% in HD vs 4.5% in PD group, p = 0.004). No patient had restrictive filling pattern. There was no difference in the prevalence of arterial hypertension and diabetes mellitus in patients with grade II vs less than grade II dysfunction. Mean CFR was similar in the HD and PD groups (2.25 ± 0.65 vs 2.36 ± 0.76, p = 0.635) and lower in patients with grade II diastolic dysfunction (1.87 ± 0.43 vs 2.44 ± 0.72, p = 0.023) and diabetes (1.70 ± 0.59 vs 2.39 ± 0.68, p = 0.04). LV mass index was negatively associated with CFR (r = - 0.308, p = 0.045).

CONCLUSION

Patients on HD had more advanced diastolic dysfunction compared to PD, independently of the presence of hypertension and diabetes. CFR did not differ between HD and PD patients, but it was significantly lower in diabetics and in patients with more advanced diastolic dysfunction.

Should We Consider the Cardiovascular System While Evaluating CKD-MBD?

Cardiovascular (CV) disease is highly prevalent in the population with chronic kidney disease (CKD), where the risk of CV death in early stages far exceeds the risk of progression to dialysis. The presence of chronic kidney disease-mineral and bone disorder (CKD-MBD) has shown a strong correlation with CV events and mortality. As a non-atheromatous process, it could be partially explained why standard CV disease-modifying drugs do not provide such an impact on CV mortality in CKD as observed in the general population. We summarize the potential association of CV comorbidities with the older (parathyroid hormone, phosphate) and newer (FGF23, Klotho, sclerostin) CKD-MBD biomarkers.

Prognostic value of heart failure in hemodialysis-dependent end-stage renal disease patients with myocardial fibrosis quantification by extracellular volume on cardiac magnetic resonance imaging

BACKGROUND

End-stage renal disease (ESRD) patients are at high cardiovascular risk, and myocardial fibrosis (MF) accounts for most of their cardiac events. The purpose of this study is to investigate the prognostic value and risk stratification of MF as measured by extracellular volume (ECV) on cardiac magnetic resonance (CMR) for heart failure (HF) in patients with hemodialysis-dependent ESRD.

METHODS

Sixty-six hemodialysis ESRD patients and 25 matched healthy volunteers were prospectively enrolled and underwent CMR to quantify multiple parameters of MF by T1 mapping and late gadolinium enhancement (LGE). All ESRD patients were followed up for 11-30 months, and the end-point met the 2016 ESC guidelines for the definition of HF.

RESULTS

Over a median follow-up of 18 months (range 11-30 months), there were 26 (39.39%) guideline-diagnosed HF patients in the entire cohort of ESRD subjects. The native T1 value was elongated, and ECV was enlarged in the HF cohort relative to the non-HF cohort and normal controls (native T1, 1360.10 ± 50.14 ms, 1319.39 ± 55.44 ms and 1276.35 ± 56.56 ms; ECV, 35.42 ± 4.42%, 31.85 ± 3.01% and 26.97 ± 1.87%; all p<0.05). In the cardiac strain analysis, ECV was significantly correlated with global radial strain (GRS) (r = - 0.501, p = 0.009), global circumferential strain (GCS) (r = 0.553, p = 0.005) and global longitudinal strain (GLS) (r = 0.507, p = 0.008) in ESRD patients with HF. Cox proportional hazard regression models revealed that ECV (hazard ratio [HR] = 1.160, 95% confidence interval: 1.022 to 1.318, p = 0.022) was the only independent predictor of HF in ESRD patients. It also had a higher diagnostic accuracy for detecting MF (area under the curve [AUC] = 0.936; 95% confidence interval: 0.864 to 0.976) than native T1 and post T1 (all p ≤ 0.002). Kaplan-Meier analysis revealed that the high-ECV group had a shorter median overall survival time than the low-ECV group (18 months vs. 20 months, log-rank p = 0.046) and that ESRD patients with high ECV were more likely to have HF.

CONCLUSIONS

Myocardial fibrosis quantification by ECV on CMR T1 mapping was shown to be an independent risk factor of heart failure, providing incremental prognostic value and risk stratification for cardiac events in ESRD patients.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR-DND-17012976, 13/12/2017, Retrospectively registered.

Protein Carbonyl Content Is a Predictive Biomarker of Eccentric Left Ventricular Hypertrophy in Hemodialysis Patients

High prevalence of left ventricular hypertrophy (LVH) and elevated oxidative stress are associated with poor outcomes in chronic hemodialysis patients. Abnormal left ventriculаr geomеtry and different geometric patterns play an important role as well. Our study analyzed the role of oxidative stress on myocardial remodeling in these patients. Plasma malondialdehyde (MDA), protein carbonyl (PC) content, and total antioxidative capacity (TAC) were investigated in 104 hemodialysis patients together with transthoracic echocardiography. Compared to patients with normal ventricular geometry, patients with LVH had increased MDA and PC plasma concentration. Multivariate analysis demonstrated that protein carbonyls, as biomarkers of oxidative protein modification, were an independent predictor of eccentric hypertrophy (eLVH), including higher LV end-diastolic diameter and LV end-diastolic volume, (β = 0.32 and β = 0.28, p < 0.001 for both). The incidence of eLVH increased progressively from the lowest to the highest baseline PC tertile (p < 0.001 for the trend) and the subjects in the former group showed a 76% greater risk of developing eLVH compared to their counterparts. After further adjustment for the potential mediators, PCs carried eLVH odds (95% confidence interval (CI)) of 1.256 (0.998-1.514), per standard deviation increase. High plasma protein carbonyls levels are a significant independent predictor of eccentric LVH in chronic hemodialysis patients.

Fibroblast growth factor 23 is induced by an activated renin-angiotensin-aldosterone system in cardiac myocytes and promotes the pro-fibrotic crosstalk between cardiac myocytes and fibroblasts

Background

Fibroblast growth factor 23 (FGF23) is discussed as a new biomarker of cardiac hypertrophy and mortality in patients with and without chronic kidney disease (CKD). We previously demonstrated that FGF23 is expressed by cardiac myocytes, enhanced in CKD and induces cardiac hypertrophy via activation of FGF receptor 4 independent of its co-receptor klotho. The impact of FGF23 on cardiac fibrosis is largely unknown.

Methods

By conducting a retrospective case-control study including myocardial autopsy samples from 24 patients with end-stage CKD and in vitro studies in cardiac fibroblasts and myocytes, we investigated the pro-fibrotic properties of FGF23.

Results

The accumulation of fibrillar collagens I and III was increased in myocardial tissue of CKD patients and correlated with dialysis vintage, klotho deficiency and enhanced cardiac angiotensinogen (AGT) expression. Using human fibrosis RT2 Profiler PCR array analysis, transforming growth factor (TGF)-β and its related TGF-β receptor/Smad complexes, extracellular matrix remodeling enzymes and pro-fibrotic growth factors were upregulated in myocardial tissue of CKD patients. FGF23 stimulated cell proliferation, migration, pro-fibrotic TGF-β receptor/Smad complexes and collagen synthesis in cultured cardiac fibroblasts. In isolated cardiac myocytes, FGF23 enhanced collagen remodeling, expression of pro-inflammatory genes and pro-survival pathways and induced pro-hypertrophic genes. FGF23 stimulated AGT expression in cardiac myocytes and angiotensin II and aldosterone, as components of the renin-angiotensin-aldosterone system (RAAS), induced FGF23 in cardiac myocytes.

Conclusions

Our data demonstrate that activated RAAS induces FGF23 expression in cardiac myocytes and thereby stimulates a pro-fibrotic crosstalk between cardiac myocytes and fibroblasts, which may contribute to myocardial fibrosis in CKD.

The relationship between R wave peak time and left ventricular mass index in patients with end-stage renal disease on hemodialysis

PURPOSE

Cardiovascular complications have been reported to be the main cause of mortality in patients with end-stage renal disease (ESRD). Although left ventricular hypertrophy is the most common clinical presentation of cardiac remodeling, cardiovascular complications may also include disturbances of the heart conduction system. The R wave peak time (RWPT) has been previously associated with left ventricular hypertrophy and myocardial ischemia. In this study, we aimed to investigate the relationship between RWPT and echocardiographic parameters in patients with ESRD.

METHODS

This study enrolled 66 patients (29 females, age 57.2 ± 12.8 years) with ESRD, and 72 controls (37 females, age 55.3 ± 10.1 years) with similar risk factors. All patients underwent electrocardiography and transthoracic echocardiography. The RWPT was defined as the interval between the onset of the QRS complex and the peak of the R or R' wave.

RESULTS

There was no significant difference in terms of clinical and demographic parameters between ESRD patients and controls. Left ventricular ejection fraction was similar between the groups. However, left atrial diameter, interventricular septal thickness, posterior wall thickness, left ventricular mass (LVM) and left ventricular mass index (LVMI) were significantly higher in patients with ESRD. Among electrocardiographic parameters, P wave and QRS complex durations and RWPT were significantly higher in patients with ESRD. Prolonged RWPT, increased LVM and LVMI were identified as associates of ESRD. Furthermore, RWPT correlated well with LVM and LVMI.

CONCLUSION

The present study demonstrated that RWPT prolonged significantly in patients with ESRD. Furthermore, prolonged RWPT has been associated with increased LVM and LVMI.

Aortic stiffness is independently associated with interstitial myocardial fibrosis by native T1 and accelerated in the presence of chronic kidney disease

BACKGROUND

Patients with chronic kidney disease (CKD) have considerable cardiovascular morbidity and mortality. Aortic stiffness is an independent predictor of cardiovascular risk and related to left ventricular remodeling and heart failure. Myocardial fibrosis is the pathophysiological hallmark of the failing heart.

METHODS AND RESULTS

An observational study of consecutive CKD patients (n = 276) undergoing comprehensive clinical cardiovascular magnetic resonance imaging. The relationship between aortic stiffness, myocardial fibrosis, left ventricular remodeling and the severity of chronic kidney disease was examined. Compared to age-gender matched controls with no known kidney disease (n = 242), CKD patients had considerably higher myocardial native T1 and central aortic PWV (p ≪ 0.001), as well as abnormal diastolic relaxation by E/e' (mean) by echocardiography (p ≪ 0.01). A third of all patients had LGE, with similar proportions for the presence and the (ischaemic and non-ischaemic) pattern between the groups. PWV was strongly associated with and age, NT-proBNP and native T1 in both groups, but not with LGE presence or type; the associations were amplified in severe CKD stages. In multivariate analyses, PWV was independently associated with native T1 in both groups (p ≪ 0.01) with near two-fold increase in adjusted R2 in the presence of CKD (native T1 (10 ms) R2, B(95%CI) CKD vs. non-CKD 0.28, 0.2(0.15-0.25) vs. 0.18, 0.1(0.06-0.15), p ≪ 0.01).

CONCLUSIONS

Aortic stiffness and interstitial myocardial fibrosis are interrelated; this association is accelerated in the presence of CKD, but independent of LGE. Our findings reiterate the significant contribution of CKD-related factors to the pathophysiology of cardiovascular remodeling.

[Zhenwu Decoction delays ventricular hypertrophy in rats with uremic cardiomyopathy]

OBJECTIVE

To investigate the inhibitory effect of Zhenwu Decoction on ventricular hypertrophy in rats with uremic cardiomyopathy and explore the mechanism.

METHODS

Cardiocytes isolated from suckling rats were divided into control group and indoxyl sulfate (IS) group, and the protein synthesis was assayed with [³H]- leucine incorporation and cellular protein expressions were detected using Western blotting. Fifty SD rats were randomly divided into sham operation group, model group, and low- and high-dose Zhenwu Decoction treatment groups, and except for those in the sham operation group, all the rats underwent 5/6 nephrectomy. Four weeks after the operation, the rats in low- and high-dose treatment groups were given Zhenwu Decoction via gavage at the dose of 4.5 g/kg and 13.5 g/kg, respectively; the rats in the sham-operated and model groups were given an equal volume of distilled water. After 4 weeks of treatment, serum levels of IS were determined, and cardiac and ventricular mass indexes were measured in the rats; cardiac ultrasound was performed and Western blotting was used to measure the expressions of BNP, p-ERK1/2, p-p38 and p-JNK in the myocardium.

RESULTS

Rat cardiomyocytes treated with IS showed significantly enhanced protein synthesis and increased expression levels of BNP, p-erk1/2, and p-p38 as compared with the control cells (P &lt; 0.01), but the expression of p-jnk was comparable between the two groups. In the animal experiment, the rats in the model group showed significantly increased serum creatinine (SCr) and urea nitrogen (BUN) levels, 24-h urine protein (24 hUpro), plasma IS level, left ventricular mass index (LVMI) and whole heart mass index (HMI) compared with those in the sham group (P &lt; 0.01); Both LVESD and LVEDD were significantly reduced and LVAWS, LVAWD, LVPWS and LVPWD were significantly increased in the model rat, which also presented with obvious cardiomyocyte hypertrophy and increased myocardial expressions of BNP, p-ERK1/2, p-p38 and p-jnk (P &lt; 0.01). Compared with the rats in the model group, the rats treated with low-dose and high-dose Zhenwu Decoction had significantly lowered levels of SCr, BUN, 24 hUpro and IS (P &lt; 0.05) and decreased LVMI and HMI; LVESD, LVEDD, LVPWS, LVAWS, and LVAWD were improved more obviously in the high-dose group, and the myocardial expressions of BNP, p-ERK1/2, p-p38 and p-JNK was significantly downregulated after the treatment.

CONCLUSIONS

Zhenwu Decoctin can reduce plasma IS levels and inhibit ventricular hypertrophy to delay ventricular remodeling in rats with uremic cardiomyopathy.

The reproducibility of cardiac magnetic resonance imaging measures of aortic stiffness and their relationship to cardiac structure in prevalent haemodialysis patients

BACKGROUND

Aortic stiffness is one of the earliest signs of cardiovascular disease (CVD) in patients with chronic kidney disease and an independent predictor of mortality. It is thought to drive left ventricular (LV) remodelling, an established biomarker for mortality. The relationship between direct and indirect measures of aortic stiffness and LV remodelling is not defined in dialysis patients, nor are the reproducibility of methods used to assess aortic stiffness using cardiac magnetic resonance (CMR) imaging.

METHODS

Using 3T CMR, we report the results of (i) the interstudy, interobserver and intra-observer reproducibility of ascending aortic distensibility (AAD), descending aortic distensibility (DAD) and aortic pulse wave velocity (aPWV) in 10 haemodialysis (HD) patients and (ii) the relationship between AAD, DAD and aPWV and LV mass index (LVMi) and LV remodelling in 70 HD patients.

RESULTS

Inter- and intra-observer variability of AAD, DAD and aPWV were excellent [intraclass correlation (ICC) > 0.9 for all]. Interstudy reproducibility of AAD was excellent {ICC 0.94 [95% confidence interval (CI) 0.78-0.99]}, but poor for DAD and aPWV [ICC 0.51 (-0.13-0.85) and 0.51 (-0.31-0.89)]. AAD, DAD and aPWV associated with LVMi on univariate analysis (β = -0.244, P = 0.04; β =-0.315, P < 0.001 and β = 0.242, P = 0.04, respectively). Only systolic blood pressure, serum phosphate and a history of CVD remained independent determinants of LVMi on multivariable linear regression.

CONCLUSIONS

AAD is the most reproducible CMR-derived measure of aortic stiffness in HD patients. CMR-derived measures of aortic stiffness were not independent determinants of LVMi in HD patients. Whether one should target blood pressure over aortic stiffness to mitigate cardiovascular risk still needs determination.

A novel biomarker of laminin turnover is associated with disease progression and mortality in chronic kidney disease

Background

Patients with chronic kidney disease (CKD) have increased risk of development of end-stage renal disease (ESRD) and early mortality. Fibrosis is the central pathogenic process in CKD and is caused by dysregulated extracellular matrix (ECM) remodeling. The laminin γ1 chain (LAMC1) is a core structural protein present in the basement membrane of several organs, including the kidneys. We hypothesized that dysregulation of LAMC1 remodeling could be associated with a higher risk of adverse clinical outcomes in patients with CKD.

Methods

A novel immunoassay targeting LG1M, a specific MMP-9-generated neo-epitope fragment of LAMC1, was developed and used to measure the levels of the fragment in urine and serum from 492 patients from the Renal Impairment in Secondary Care (RIISC) study, a prospective cohort of patients with high-risk CKD. Patients were monitored for a median follow-up time of 3.5 years. Associations between serum and urine LG1M levels and progression of CKD at 12 months were assessed by a multivariable logistic regression model. The association with ESRD or mortality was assessed by Kaplan-Meier survival curves and Cox proportional hazards regression.

Results

Forty-six (11%) of the 416 patients who reached 12-month follow-up had progression of CKD; during the study follow-up, 125 patients (25.4%) developed ESRD and 71 patients (14.4%) died. Serum and urine levels of LG1M correlated with baseline eGFR (r = -0.43, p<0.0001 and r = -0.17, p = 0.0002, respectively). Serum levels of LG1M were higher in patients with one-year progression of CKD compared to those who did not progress (p<0.01). Baseline serum levels of LG1M were associated with development of ESRD (HR 3.2, 95% CI 1.99–5.2 for patients in the highest LG1M tertile compared to patient in the lowest tertile). Baseline urinary levels of LG1M (uLG1M) were significantly associated with mortality (HR 5.0, 95% CI 2.8–8.9, p<0.0001 for patients in the highest LG1M tertile compared to patients in the lowest tertile). Urine LG1M was retained in the model for prediction of mortality (HR per standard deviation of uLG1M: 1.01, 95% CI 1.00–1.02, p = 0.001).

Conclusions

LG1M, a marker of basement membrane remodeling, is increased in serum and urine of patients with CKD and levels are associated with one-year disease progression, development of ESRD, and mortality.

Cardiotoxicity of Uremic Toxins: A Driver of Cardiorenal Syndrome

Cardiovascular disease (CVD) is highly prevalent in the setting of chronic kidney disease (CKD). Such coexistence of CVD and CKD—the so-called “cardiorenal or renocardiac syndrome”—contributes to exponentially increased risk of cardiovascular (CV) mortality. Uremic cardiomyopathy is a characteristic cardiac pathology commonly found in CKD. CKD patients are also predisposed to heart rhythm disorders especially atrial fibrillation. Traditional CV risk factors as well as known CKD-associated CV risk factors such as anemia are insufficient to explain CV complications in the CKD population. Accumulation of uremic retention solutes is a hallmark of impaired renal excretory function. Many of them have been considered inert solutes until their biological toxicity is unraveled and they become accepted as “uremic toxins”. Direct cardiotoxicity of uremic toxins has been increasingly demonstrated in recent years. This review offers a mechanistic insight into the pathological cardiac remodeling and dysfunction contributed by uremic toxins with a main focus on fibroblastic growth factor-23, an emerging toxin playing a central role in the chronic kidney disease–mineral bone disorder, and the two most investigated non-dialyzable protein-bound uremic toxins, indoxyl sulfate and p-cresyl sulfate. Potential therapeutic strategies that could address these toxins and their relevant mediated pathways since pre-dialysis stages are also discussed.

Gut Microbiota and Cardiovascular Uremic Toxicities

Cardiovascular disease (CVD) remains a major cause of high morbidity and mortality in patients with chronic kidney disease (CKD). Numerous CVD risk factors in CKD patients have been described, but these do not fully explain the high pervasiveness of CVD or increased mortality rates in CKD patients. In CKD the loss of urinary excretory function results in the retention of various substances referred to as "uremic retention solutes". Many of these molecules have been found to exert toxicity on virtually all organ systems of the human body, leading to the clinical syndrome of uremia. In recent years, an increasing body of evidence has been accumulated that suggests that uremic toxins may contribute to an increased cardiovascular disease (CVD) burden associated with CKD. This review examined the evidence from several clinical and experimental studies showing an association between uremic toxins and CVD. Special emphasis is addressed on emerging data linking gut microbiota with the production of uremic toxins and the development of CKD and CVD. The biological toxicity of some uremic toxins on the myocardium and the vasculature and their possible contribution to cardiovascular injury in uremia are also discussed. Finally, various therapeutic interventions that have been applied to effectively reduce uremic toxins in patients with CKD, including dietary modifications, use of prebiotics and/or probiotics, an oral intestinal sorbent that adsorbs uremic toxins and precursors, and innovative dialysis therapies targeting the protein-bound uremic toxins are also highlighted. Future studies are needed to determine whether these novel therapies to reduce or remove uremic toxins will reduce CVD and related cardiovascular events in the long-term in patients with chronic renal failure.

Subjective Global Assessment-Dialysis Malnutrition Score and cardiovascular risk in hemodialysis patients: an observational cohort study

BACKGROUND

Malnutrition is an important risk factor for cardiovascular mortality in hemodialysis (HD) patients. However, current malnutrition biomarkers seem unable to accurately estimate the role of malnutrition in predicting cardiovascular risk. Our aim was to investigate the role of the Subjective Global Assessment-Dialysis Malnutrition Score (SGA-DMS) compared to two well-recognized comorbidity scores-Charlson Comorbidity Index (CCI) and modified CCI (excluding age-factor) (mCCI)-in predicting cardiovascular events in HD patients.

METHODS

In 86 maintenance HD patients followed from June 2015 to June 2017, we analyzed biohumoral data and clinical scores as risk factors for cardiovascular events (acute heart failure, acute coronary syndrome and stroke). Their impact on outcome was investigated by linear regression, Cox regression models and ROC analysis.

RESULTS

Cardiovascular events occurred in 26/86 (30%) patients during the 2-year follow-up. Linear regression showed only age and dialysis vintage to be positively related to SGA-DMS: B 0.21 (95% CI 0.01; 0.30) p 0.05, and B 0.24 (0.09; 0.34) p 0.02, respectively, while serum albumin, normalized protein catabolic rate (nPCR) and dialysis dose (Kt/V) were negatively related to SGA-DMS: B - 1.29 (- 3.29; - 0.81) p 0.02; B - 0.08 (- 1.52; - 0.35) p 0.04 and B - 2.63 (- 5.25; - 0.22) p 0.03, respectively. At Cox regression analysis, SGA-DMS was not a risk predictor for cardiovascular events: HR 1.09 (0.9; 1.22), while both CCI and mCCI were significant predictors: HR 1.43 (1.13; 1.87) and HR 1.57 (1.20; 2.06) also in Cox adjusted models. ROC analysis reported similar AUCs for CCI and mCCI: 0.72 (0.60; 0.89) p 0.00 and 0.70 (0.58; 0.82) p 0.00, respectively, compared to SGA-DMS 0.56 (0.49; 0.72) p 0.14.

CONCLUSIONS

SGA-DMS is not a superior and significant prognostic tool compared to CCI and mCCI in assessing cardiovascular risk in HD patients, even it allows to appraise both malnutrition and comorbidity status.

Hemodialysis-induced cardiovascular disease

More than half of all deaths among end stage renal disease (ESRD) patients are due to cardiovascular disease (CVD). Cardiovascular changes secondary to renal dysfunction, including fluid overload, uremic cardiomyopathy, secondary hyperparathyroidism, anemia, altered lipid metabolism, and accumulation of gut microbiota-derived uremic toxins like trimethylamine N-oxidase, contribute to the high risk for CVD in the ESRD population. In addition, conventional hemodialysis (HD) itself poses myocardial stress and injury on the already compromised cardiovascular system in uremic patients. This review will provide an overview of cardiovascular changes in chronic kidney disease and ESRD, a description of reported mechanisms for HD-induced myocardial injury, comparison of HD with other treatment modalities in the context of CVD, and possible management strategies.

The association between soluble klotho and cardiovascular parameters in chronic kidney disease: results from the KNOW-CKD study

BACKGROUND

Klotho, a protein linked to aging, has emerged as a pivotal player in mineral bone metabolism and might explain the relationship between chronic kidney disease (CKD) and cardiovascular disease (CVD). The present study aimed to investigate the association between serum klotho and cardiac parameters from a large-scale Korean CKD cohort.

METHODS

We analyzed 2101 participants from KoreaN Cohort Study for Outcome in Patients With Chronic Kidney Disease (KNOW-CKD) cohort who had been measured for serum klotho levels. Left ventricular hypertrophy evaluated by left ventricular mass index (LVMI) and arterial stiffness measured by brachial-to-ankle pulse wave velocity (baPWV) were explored as cardiovascular parameters.

RESULTS

Patients were 53.6 ± 12.2 years old and 61.1% were male. The mean estimated glomerular filtration rate (eGFR) was 53.0 ± 30.7 mL/min/1.73m². The median serum klotho level was 536 (interquartile range [IQR]: 420-667) pg/mL. Advanced CKD stages were associated with lower serum klotho levels (P < 0.001, P for linear trend < 0.001). Ascending quartiles of klotho were significantly associated with decreased LMVI (P < 0.001, P for linear trend< 0.001). A multivariable linear regression model showed serum klotho had a significant inverse association with LVMI (β - 0.04; 95% CI [confidence interval] -0.004, - 0.00007; P = 0.041). However, there was no significant association between serum klotho and baPWV after adjustment (β 0.003; 95% CI -0.04, 0.05; P = 0.876).

TRIAL REGISTRATION

This trial was registered on ClinicalTrials.gov on 28 June 2012 ( NCT01630486 ).

CONCLUSIONS

Serum klotho was an independent biomarker of LVMI, but not arterial stiffness.

Impact of Altered Mineral Metabolism on Pathological Cardiac Remodeling in Elevated Fibroblast Growth Factor 23

Clinical and experimental studies indicate a possible link between high serum levels of fibroblast growth factor 23 (FGF23), phosphate, and parathyroid hormone (PTH), deficiency of active vitamin D (1,25D) and klotho with the development of pathological cardiac remodeling, i.e., left ventricular hypertrophy and myocardial fibrosis, but a causal link has not been established so far. Here, we investigated the cardiac phenotype in klotho hypomorphic (kl/kl) mice and Hyp mice, two mouse models of elevated FGF23 levels and klotho deficiency, but differing in parameters of mineral metabolism, by using histology, quantitative real-time PCR, immunoblot analysis, and serum and urine biochemistry. Additionally, the specific impact of calcium, phosphate, PTH, and 1,25D on hypertrophic growth of isolated neonatal rat cardiac myocytes was investigated in vitro. Kl/kl mice displayed high serum Fgf23 levels, increased relative heart weight, enhanced cross-sectional area of individual cardiac myocytes, activated cardiac Fgf23/Fgf receptor (Fgfr) 4/calcineurin/nuclear factor of activated T cell (NFAT) signaling, and induction of pro-hypertrophic NFAT target genes including Rcan1, bMHC, brain natriuretic peptide (BNP), and atrial natriuretic peptide (ANP) as compared to corresponding wild-type (WT) mice. Investigation of fibrosis-related molecules characteristic for pathological cardiac remodeling processes demonstrated ERK1/2 activation and enhanced expression of Tgf-β1, collagen I, and Mmp2 in kl/kl mice than in WT mice. In contrast, despite significantly elevation of serum and cardiac Fgf23, and reduced renal klotho expression, Hyp mice showed no signs of pathological cardiac remodeling. Kl/kl mice showed enhanced serum calcium and phosphate levels, while Hyp mice showed unchanged serum calcium levels, lower serum phosphate, and elevated serum iPTH concentrations compared to corresponding WT mice. In cultured cardiac myocytes, treatment with both calcium or phosphate significantly upregulated endogenous Fgf23 mRNA expression and stimulated hypertrophic cell growth and expression of pro-hypertrophic genes. The treatment with PTH induced hypertrophic cell growth only, and stimulation with 1,25D had no significant effects. In conclusion, our data indicate that Hyp mice, in contrast to kl/kl mice appear to be protected from pathological cardiac remodeling during conditions of high FGF23 levels and klotho deficiency, which may be due, at least in part, to differences in mineral metabolism alterations, i.e., hypophosphatemia and lack of hypercalcemia.

Chronic Kidney Disease and Disproportionally Increased Cardiovascular Damage: Does Oxidative Stress Explain the Burden?

Chronic kidney disease (CKD) patients are among the groups at the highest risk for cardiovascular disease and significantly shortened remaining lifespan. CKD enhances oxidative stress in the organism with ensuing cardiovascular damage. Oxidative stress in uremia is the consequence of higher reactive oxygen species (ROS) production, whereas attenuated clearance of pro-oxidant substances and impaired antioxidant defenses play a complementary role. The pathophysiological mechanism underlying the increased ROS production in CKD is at least partly mediated by upregulation of the intrarenal angiotensin system. Enhanced oxidative stress in the setting of the uremic milieu promotes enzymatic modification of circulating lipids and lipoproteins, protein carbamylation, endothelial dysfunction via disruption of nitric oxide (NO) pathways, and activation of inflammation, thus accelerating atherosclerosis. Left ventricular hypertrophy (LVH) and heart failure are hallmarks of CKD. NADPH oxidase activation, xanthine oxidase, mitochondrial dysfunction, and NO-ROS are the main oxidative pathways leading to LVH and the cardiorenal syndrome. Finally, a subset of antioxidant enzymes, the paraoxonases (PON), deserves special attention due to abundant clinical evidence accumulated regarding reduced serum PON1 activity in CKD as a contributor to the increased burden of cardiovascular disease. Future, meticulously designed studies are needed to assess the effects of antioxidant therapy on patients with CKD.

Cardiac actions of fibroblast growth factor 23

Fibroblast growth factors (FGF) are mitogenic signal mediators that induce cell proliferation and survival. Although cardiac myocytes are post-mitotic, they have been shown to be able to respond to local and circulating FGFs. While precise molecular mechanisms are not well characterized, some FGF family members have been shown to induce cardiac remodeling under physiologic conditions by mediating hypertrophic growth in cardiac myocytes and by promoting angiogenesis, both events leading to increased cardiac function and output. This FGF-mediated physiologic scenario might transition into a pathologic situation involving cardiac cell death, fibrosis and inflammation, and eventually cardiac dysfunction and heart failure. As discussed here, cardiac actions of FGFs - with the majority of studies focusing on FGF2, FGF21 and FGF23 - and their specific FGF receptors (FGFR) and precise target cell types within the heart, are currently under experimental investigation. Especially cardiac effects of endocrine FGFs entered center stage over the past five years, as they might provide communication routes that couple metabolic mechanisms, such as bone-regulated phosphate homeostasis, or metabolic stress, such as hyperphosphatemia associated with kidney injury, with changes in cardiac structure and function. In this context, it has been shown that elevated serum FGF23 can directly tackle cardiac myocytes via FGFR4 thereby contributing to cardiac hypertrophy in models of chronic kidney disease, also called uremic cardiomyopathy. Precise characterization of FGFs and their origin and regulation of expression, and even more importantly, the identification of the FGFR isoforms that mediate their cardiac actions should help to develop novel pharmacological interventions for heart failure, such as FGFR4 inhibition to tackle uremic cardiomyopathy.

The importance of accurate measurement of aortic stiffness in patients with chronic kidney disease and end-stage renal disease

Cardiovascular (CV) disease is the leading cause of death in chronic kidney disease (CKD) and end-stage renal disease (ESRD). A key driver in this pathology is increased aortic stiffness, which is a strong, independent predictor of CV mortality in this population. Aortic stiffening is a potentially modifiable biomarker of CV dysfunction and in risk stratification for patients with CKD and ESRD. Previous work has suggested that therapeutic modification of aortic stiffness may ameliorate CV mortality. Nevertheless, future clinical implementation relies on the ability to accurately and reliably quantify stiffness in renal disease. Pulse wave velocity (PWV) is an indirect measure of stiffness and is the accepted standard for non-invasive assessment of aortic stiffness. It has typically been measured using techniques such as applanation tonometry, which is easy to use but hindered by issues such as the inability to visualize the aorta. Advances in cardiac magnetic resonance imaging now allow direct measurement of stiffness, using aortic distensibility, in addition to PWV. These techniques allow measurement of aortic stiffness locally and are obtainable as part of a comprehensive, multiparametric CV assessment. The evidence cannot yet provide a definitive answer regarding which technique or parameter can be considered superior. This review discusses the advantages and limitations of non-invasive methods that have been used to assess aortic stiffness, the key studies that have assessed aortic stiffness in patients with renal disease and why these tools should be standardized for use in clinical trial work.