Electrocardiographic abnormalities and uremic cardiomyopathy

Atherosclerotic Diseases in Chronic Kidney Disease

Patients with chronic kidney disease (CKD) have a high incidence of atherosclerotic diseases, such as ischemic heart disease, cerebrovascular disease, and peripheral arterial disease. To prevent the incidence of atherosclerotic cardiovascular disease in patients with CKD, the pathology of arteriosclerosis should be determined. Vascular calcification is a characteristic of arteriosclerosis in patients with CKD. Recent studies have reported that coronary artery calcification is associated with acute coronary syndromes. CKD is frequently associated with heart failure. Furthermore, recent evidence suggests that coronary artery calcification affects asymptomatic myocardial ischemia. Hyperphosphatemia and calciprotein particles may be involved in the pathology of vascular calcification. Controlling the progression of vascular calcification and classical atherosclerotic risk factors is important to prevent the occurrence of atherosclerotic diseases in CKD.

Left Ventricular Hypertrophy After Renal Transplantation: Systematic Review and Meta-analysis

Background

Left ventricular hypertrophy (LVH) in patients with end stage renal disease undergoing renal replacement is linked to an increased risk for cardiovascular diseases. Dialysis does not completely prevent or correct this abnormality, and the evidence for kidney transplantation (KT) varies. This analysis aims to explore the relationship between KT and LVH.

Methods

MEDLINE and Scopus were systematically searched in October 2023. All cross-sectional and longitudinal studies that fulfilled our inclusion criteria were included. Outcome was left ventricular mass index (LVMI) changes. We conducted a meta-analysis using a random effects model. Meta-regression was applied to examine the LVMI changes dependent on various covariates. Sensitivity analysis was used to handle outlying or influential studies and address publication bias.

Results

From 7416 records, 46 studies met the inclusion criteria with 4122 included participants in total. Longitudinal studies demonstrated an improvement of LVMI after KT -0.44 g/m2 (-0.60 to -0.28). Blood pressure was identified as a predictor of LVMI change. A younger age at the time of KT and well-controlled anemia were also associated with regression of LVH. In studies longitudinally comparing patients on dialysis and renal transplant recipients, no difference was detected -0.09 g/m2 (-0.33 to 0.16). Meta-regression using changes of systolic blood pressure as a covariate showed an association between higher blood pressure and an increase in LVMI, regardless of the modality of renal replacement treatment.

Conclusions

In conclusion, our results indicated a potential cardiovascular benefit, defined as the regression of LVH, after KT. This benefit was primarily attributed to improved blood pressure control rather than the transplantation itself.

Renal and cardiovascular prognostic significance of echocardiographic early diastolic mitral annular velocity in IgA nephropathy

In chronic kidney disease (CKD), as in IgA nephropathy (IgAN), cardiovascular (CV) mortality and morbidity are many times higher than in the general population, and diastolic dysfunction (LVDD) has prognostic significance as well. Tissue Doppler Echocardiography (TDI) is another method for measuring myocardial contractility and determining diastolic dysfunction. 79 IgAN patients (age 46 ± 11 years) with CKD stages 1-3 were investigated and followed for 70 ± 28.7 months. Doppler echocardiography was used to measure the E (early) and A (late) waves, as well as the E wave deceleration time (EDT) during mitral inflow. TDI was used to measure early (Ea) and late (Aa) diastolic velocities (lateral and septal basal wall fragment average). From these, we calculated the E/Ea and Ea/Aa ratios. The primary combined endpoints were total mortality, major CV events, and end-stage renal disease, and the secondary endpoints were cardiovascular or renal (eGFR decreased below 15 ml/min/1.73 m2 or renal replacement therapy was started). Patients with decreased Ea (< 13 cm/s) had significantly more endpoints (20/42 vs. 3/37; p = 0.001) than patients with higher Ea (≥ 13 cm/s). The secondary renal endpoints were also significantly higher (p = 0.004). In a multivariate model, the eGFR showed independent correlation with the E/A ratio (r = 0.466; p < 0.01), EDT (r = - 0.270; p < 0.01), Ea/Aa ratio (r = 0.455; p < 0.01), and decreased Ea (r = 0.544; p < 0.01). Independent factors influencing Ea were only EDT by uni- and multivariate regression but age and albuminuria by logistic regression. Decreased Ea measured by TDI seems to be an eligible factor to predict the prognosis of IgA nephropathy. The decreased Ea may be a helpful parameter to identify high-risk CKD patients.

Cardiomyopathy in chronic kidney disease: clinical features, biomarkers and the contribution of murine models in understanding pathophysiology

The cardiorenal syndrome (CRS) is described as a multi-organ disease encompassing bidirectionally heart and kidney. In CRS type 4, chronic kidney disease (CKD) leads to cardiac injury. Different pathological mechanisms have been identified to contribute to the establishment of CKD-induced cardiomyopathy, including a neurohormonal dysregulation, disturbances in the mineral metabolism and an accumulation of uremic toxins, playing an important role in the development of inflammation and oxidative stress. Combined, this leads to cardiac dysfunction and cardiac pathophysiological and morphological changes, like left ventricular hypertrophy, myocardial fibrosis and cardiac electrical changes. Given that around 80% of dialysis patients suffer from uremic cardiomyopathy, the study of cardiac outcomes in CKD is clinically highly relevant. The present review summarizes clinical features and biomarkers of CKD-induced cardiomyopathy and discusses underlying pathophysiological mechanisms recently uncovered in the literature. It discloses how animal models have contributed to the understanding of pathological kidney-heart crosstalk, but also provides insights into the variability in observed effects of CKD on the heart in different CKD mouse models, covering both "single hit" as well as "multifactorial hit" models. Overall, this review aims to support research progress in the field of CKD-induced cardiomyopathy.

Diagnosis of cardiovascular disease in patients with chronic kidney disease

Patients with chronic kidney disease (CKD) are at high risk of cardiovascular disease (CVD) and cardiovascular death. Identifying and monitoring cardiovascular complications and hypertension is important for managing patients with CKD or kidney failure and transplant recipients. Biomarkers of myocardial ischaemia, such as troponins and electrocardiography (ECG), have limited utility for diagnosing cardiac ischaemia in patients with advanced CKD. Dobutamine stress echocardiography, myocardial perfusion scintigraphy and dipyridamole stress testing can be used to detect coronary disease in these patients. Left ventricular hypertrophy and left ventricular dysfunction can be detected and monitored using various techniques with differing complexity and cost, including ECG, echocardiography, nuclear magnetic resonance, CT and myocardial scintigraphy. Atrial fibrillation and other major arrhythmias are common in all stages of CKD, and ambulatory heart rhythm monitoring enables precise time profiling of these disorders. Screening for cerebrovascular disease is only indicated in asymptomatic patients with autosomal dominant polycystic kidney disease. Standardized blood pressure is recommended for hypertension diagnosis and treatment monitoring and can be complemented by ambulatory blood pressure monitoring. Judicious use of these diagnostic techniques may assist clinicians in detecting the whole range of cardiovascular alterations in patients with CKD and enable timely treatment of CVD in this high-risk population.

Relationship between arterial stiffness, left ventricular diastolic function, and renal function in chronic kidney disease

AIM

In chronic kidney disease, IgA nephropathy, and left ventricular diastolic dysfunction have prognostic significance as well. However, the relationship between diastolic dysfunction, arterial stiffness, and renal function has not been fully elucidated.

METHODS

79 IgA nephropathy patients (aged 46 ± 11 years) and 50 controls were investigated. Tissue Doppler imaging was used to measure early (Ea) and late (Aa) diastolic velocities. Arterial stiffness was measured by a photoplethysmographic (stiffness index (SI)) and an oscillometric method (aortic pulse wave velocity (PWVao)).

RESULTS

We compared the IgAN patients to a similar cardiovascular risk group with a preserved eGFR. A strong correlation was found between Ea/Aa and SI (p < 0.001), also with PWVao (p < 0.001), just in IgAN, and with eGFR (p < 0.001) in both groups. IgAN patients were divided into groups CKD1-2 vs. CKD3-5. In the CKD 3-5 group, the incidence of diastolic dysfunction increased significantly: 39% vs. 72% (p = 0.003). Left ventricle rigidity (LVR) was calculated, which showed a close correlation with SI (p = 0.009) and eGFR (p = 0.038). By linear regression analysis, the independent predictors of SI were age, E/A, and E/Ea; SI was the predictor of LVR; and E/A and hypertension were the predictors of eGFR.

CONCLUSION

In chronic kidney disease, increased cardiac rigidity and vascular stiffness coexist with decreased renal function, which is directly connected to diastolic dysfunction and vascular stiffness. On the basis of comparing the CKD group to the control group, vascular alterations in very early CKD can be identified.

Sodium Bicarbonate Treatment and Vascular Function in CKD: A Randomized, Double-Blind, Placebo-Controlled Trial

SIGNIFICANCE STATEMENT

Lower serum bicarbonate levels, even within the normal range, are strongly linked to risks of cardiovascular disease in CKD, possibly by modifying vascular function. In this randomized, controlled trial, treatment with sodium bicarbonate (NaHCO 3 ) did not improve vascular endothelial function or reduce arterial stiffness in participants with CKD stage 3b-4 with normal serum bicarbonate levels. In addition, NaHCO 3 treatment did not reduce left ventricular mass index. NaHCO 3 did increase plasma bicarbonate levels and urinary citrate excretion and reduce urinary ammonium excretion, indicating that the intervention was indeed effective. NaHCO 3 therapy was safe with no significant changes in BP, weight, or edema. These results do not support the use of NaHCO 3 for vascular dysfunction in participants with CKD.

BACKGROUND

Lower serum bicarbonate levels, even within the normal range, are strongly linked to risks of cardiovascular disease in CKD, possibly by modifying vascular function. Prospective interventional trials with sodium bicarbonate (NaHCO 3 ) are lacking.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial examining the effect of NaHCO 3 on vascular function in 109 patients with CKD stage 3b-4 (eGFR 15-44 ml/min per 1.73 m 2 ) with normal serum bicarbonate levels (22-27 mEq/L). Participants were randomized 1:1 to NaHCO 3 or placebo at a dose of 0.5 mEq/lean body weight-kg per day for 12 months. The coprimary end points were change in brachial artery flow-mediated dilation (FMD) and change in aortic pulse wave velocity over 12 months.

RESULTS

Ninety patients completed this study. After 12 months, plasma bicarbonate levels increased significantly in the NaHCO 3 group compared with placebo (mean [SD] difference between groups 1.35±2.1, P = 0.003). NaHCO 3 treatment did not result in a significant improvement in aortic pulse wave velocity from baseline. NaHCO 3 did result in a significant increase in flow-mediated dilation after 1 month; however, this effect disappeared at 6 and 12 months. NaHCO 3 resulted in a significant increase in 24-hour urine citrate and pH and a significant decrease in 24-hour urine ammonia. There was no significant change in left ventricular mass index, ejection fraction, or eGFR with NaHCO 3 . NaHCO 3 treatment was safe and well-tolerated with no significant changes in BP, antihypertensive medication, weight, plasma calcium, or potassium levels.

CONCLUSION

Our results do not support the use of NaHCO 3 for vascular dysfunction in participants with CKD and normal serum bicarbonate levels.

Deep learning-based electrocardiographic screening for chronic kidney disease

BACKGROUND

Undiagnosed chronic kidney disease (CKD) is a common and usually asymptomatic disorder that causes a high burden of morbidity and early mortality worldwide. We developed a deep learning model for CKD screening from routinely acquired ECGs.

METHODS

We collected data from a primary cohort with 111,370 patients which had 247,655 ECGs between 2005 and 2019. Using this data, we developed, trained, validated, and tested a deep learning model to predict whether an ECG was taken within one year of the patient receiving a CKD diagnosis. The model was additionally validated using an external cohort from another healthcare system which had 312,145 patients with 896,620 ECGs between 2005 and 2018.

RESULTS

Using 12-lead ECG waveforms, our deep learning algorithm achieves discrimination for CKD of any stage with an AUC of 0.767 (95% CI 0.760-0.773) in a held-out test set and an AUC of 0.709 (0.708-0.710) in the external cohort. Our 12-lead ECG-based model performance is consistent across the severity of CKD, with an AUC of 0.753 (0.735-0.770) for mild CKD, AUC of 0.759 (0.750-0.767) for moderate-severe CKD, and an AUC of 0.783 (0.773-0.793) for ESRD. In patients under 60 years old, our model achieves high performance in detecting any stage CKD with both 12-lead (AUC 0.843 [0.836-0.852]) and 1-lead ECG waveform (0.824 [0.815-0.832]).

CONCLUSIONS

Our deep learning algorithm is able to detect CKD using ECG waveforms, with stronger performance in younger patients and more severe CKD stages. This ECG algorithm has the potential to augment screening for CKD.

A retrospective study of baseline peritoneal transport character and left ventricular hypertrophy in incident peritoneal dialysis patients: interrelationship and prognostic impacts

BACKGROUND

Left ventricular hypertrophy is associated with adverse outcomes among peritoneal dialysis patients. The aim of this study was to evaluate the prognostic impact of baseline left ventricular hypertrophy and its relationship with baseline peritoneal transfer characteristics in peritoneal dialysis patients.

METHODS

We enrolled 151 incident peritoneal dialysis patients to perform a multicentric retrospective cohort study since January 1, 2017 to January 31, 2021. Patients were grouped based on baseline dialysate-to-plasma creatinine ratio at 4 h as follows: low (<0.50), low average (0.5-0.64), high average (0.65-0.80) and high (≥0.81). Echocardiography and clinic data were recorded yearly. The Cox proportional hazards models and competing risk model were used to evaluate patients' survival. Generalized linear mixed models were performed to explore risk factors associated with left ventricular hypertrophy.

RESULTS

During a median follow-up period of 33 months (range, 16-48 months), 21 (13.9%) patients died, including 16 (10.60%) cardiovascular deaths. Controlling the competing risks of switching to hemodialysis, kidney transplantation and loss to follow-up, baseline left ventricular hypertrophy was an independent risk factor for all-cause mortality (subdistribution hazard ratio, 2.645; 95% confidence interval, 1.156-6.056; p = 0.021). Baseline high and high average transport status were positively related to left ventricular mass index and left atrium diameter 2 years after PD initiation.

CONCLUSION

Baseline fast peritoneal solute transport rate may be an effect factor for aggravating left ventricular hypertrophy which predicted poor outcomes for peritoneal dialysis patients. The findings offered important ideas for further prospective intervention study.

Left ventricular dysfunction with preserved ejection fraction: the most common left ventricular disorder in chronic kidney disease patients

Chronic kidney disease (CKD) is a risk factor for premature cardiovascular disease. As kidney function declines, the presence of left ventricular abnormalities increases such that by the time kidney replacement therapy is required with dialysis or kidney transplantation, more than two-thirds of patients have left ventricular hypertrophy. Historically, much research in nephrology has focussed on the structural and functional aspects of cardiac disease in CKD, particularly using echocardiography to describe these abnormalities. There is a need to translate knowledge around these imaging findings to clinical outcomes such as unplanned hospital admission with heart failure and premature cardiovascular death. Left ventricular hypertrophy and cardiac fibrosis, which are common in CKD, predispose to the clinical syndrome of heart failure with preserved left ventricular ejection fraction (HFpEF). There is a bidirectional relationship between CKD and HFpEF, whereby CKD is a risk factor for HFpEF and CKD impacts outcomes for patients with HFpEF. There have been major improvements in outcomes for patients with heart failure and reduced left ventricular ejection fraction as a result of several large randomized controlled trials. Finding therapy for HFpEF has been more elusive, although recent data suggest that sodium-glucose cotransporter 2 inhibition offers a novel evidence-based class of therapy that improves outcomes in HFpEF. These observations have emerged as this class of drugs has also become the standard of care for many patients with proteinuric CKD, suggesting that there is now hope for addressing the combination of HFpEF and CKD in parallel. In this review we summarize the epidemiology, pathophysiology, diagnostic strategies and treatment of HFpEF with a focus on patients with CKD.

Association between Anti-Erythropoietin Receptor Antibodies and Cardiac Function in Patients on Hemodialysis: A Multicenter Cross-Sectional Study

Cardiac dysfunction is an important prognostic predictor of cardiovascular mortality in patients on hemodialysis (HD). Erythropoietin (EPO) has been reported to improve cardiac function by binding to the EPO receptor (EPOR) on cardiomyocytes. This study investigated whether anti-EPOR antibodies were associated with left ventricular cardiac function in patients undergoing HD. This multicenter, cross-sectional observational study included 377 patients (median age, 70 years; 267 (70.8%) males) with chronic kidney disease (CKD) undergoing stable maintenance HD. Serum levels of anti-EPOR antibodies were measured, and echocardiography was used to assess the left ventricular mass index (LVMI) and left ventricular ejection fraction (LVEF). Anti-EPOR antibodies were found in 17 patients (4.5%). LVMI was greater (median of 135 g/m2 vs. 115 g/m2, p = 0.042), and the prevalence of LVEF < 50% was higher (35.3% vs. 15.6%, p = 0.032) in patients with anti-EPOR antibodies than in those without. Multivariable linear regression and logistic regression analysis (after adjusting for known risk factors of heart failure) revealed that anti-EPOR antibodies were independently associated with LVMI (coefficient 16.2%; 95% confidence interval (CI) 1.0−35.0%, p = 0.043) and LVEF <50% (odds ratio 3.20; 95% CI 1.05−9.73, p = 0.041). Thus, anti-EPOR antibody positivity was associated with left ventricular dysfunction in patients undergoing HD.

Left ventricular myocardial mass index associated with cardiovascular and renal prognosis in IgA nephropathy

Introduction

In chronic kidney disease (CKD), like in IgA nephropathy (IgAN), cardiovascular (CV) mortality and morbidity are many times higher than in the general population, and left ventricular hypertrophy (LVH) is an independent risk factor for CV disease. This follow-up study investigated the association between left ventricular mass index (LVMI) and renal or cardiovascular outcomes.

Methods

We examined 118 IgAN patients prospectively. LVMI and LV geometry was investigated using echocardiography. The primary combined endpoints were total mortality, major CV events, and end-stage renal disease. Secondary endpoints, i.e.—cardiovascular or renal endpoints,—were also examined separately.

Results

Sixty seven percent were males, mean age 53.5 ± 13.5. Mean follow-up time: 184 months. LVMI inversely correlated with eGFR (corr. coefficient: -0.365; p < 0.01). We divided the patients into two groups based on the LVMI cut-off suggested by the literature. The presence of LVH caused a worse prognosis in primary (p < 0.001), renal endpoints (p = 0.01), and also in CV endpoints (p = 0.001). The higher LVMI in men significantly worsened the prognosis in all endpoints. Concentric hypertrophy meant a worse prognosis. Independent predictors of LVMI were gender and eGFR in uni- and multivariate regression and hemoglobin levels only in logistic regression. Independent predictors of the primary endpoint were LVMI, eGFR, gender, obesity, HT, DM, and metabolic syndrome in Cox regression analysis.

Conclusion

Increased LVMI may predict the progression to end-stage renal disease and CV events in IgAN. Determining LVMI may be a useful parameter not only in CV risk but also in the stratification of renal risk in CKD.

SIRPα Mediates IGF1 Receptor in Cardiomyopathy Induced by Chronic Kidney Disease

BACKGROUND

Chronic kidney disease (CKD) is characterized by increased myocardial mass despite near-normal blood pressure, suggesting the presence of a separate trigger. A potential driver is SIRPα (signal regulatory protein alpha)-a mediator impairing insulin signaling. The objective of this study is to assess the role of circulating SIRPα in CKD-induced adverse cardiac remodeling.

METHODS

SIRPα expression was evaluated in mouse models and patients with CKD. Specifically, mutant, muscle-specific, or cardiac muscle-specific SIRPα KO (knockout) mice were examined after subtotal nephrectomy. Cardiac function was assessed by echocardiography. Metabolic responses were confirmed in cultured muscle cells or cardiomyocytes.

RESULTS

We demonstrate that SIRPα regulates myocardial insulin/IGF1R (insulin growth factor-1 receptor) signaling in CKD. First, in the serum of both mice and patients, SIRPα was robustly secreted in response to CKD. Second, cardiac muscle upregulation of SIRPα was associated with impaired insulin/IGF1R signaling, myocardial dysfunction, and fibrosis. However, both global and cardiac muscle-specific SIRPα KO mice displayed improved cardiac function when compared with control mice with CKD. Third, both muscle-specific or cardiac muscle-specific SIRPα KO mice did not significantly activate fetal genes and maintained insulin/IGF1R signaling with suppressed fibrosis despite the presence of CKD. Importantly, SIRPα directly interacted with IGF1R. Next, rSIRPα (recombinant SIRPα) protein was introduced into muscle-specific SIRPα KO mice reestablishing the insulin/IGF1R signaling activity. Additionally, overexpression of SIRPα in myoblasts and cardiomyocytes impaired pAKT (phosphorylation of AKT) and insulin/IGF1R signaling. Furthermore, myotubes and cardiomyocytes, but not adipocytes treated with high glucose or cardiomyocytes treated with uremic toxins, stimulated secretion of SIRPα in culture media, suggesting these cells are the origin of circulating SIRPα in CKD. Both intracellular and extracellular SIRPα exert biologically synergistic effects impairing intracellular myocardial insulin/IGF1R signaling.

CONCLUSIONS

Myokine SIRPα expression impairs insulin/IGF1R functions in cardiac muscle, affecting cardiometabolic signaling pathways. Circulating SIRPα constitutes an important readout of insulin resistance in CKD-induced cardiomyopathy.

Identification of Major Risk Factors and Non-linear Effects to the Development of Left Ventricular Hypertrophy in Chronic Kidney Disease by Constructing and Validation of Nomograms

Background

Left ventricular hypertrophy (LVH) is a common cardiovascular complication among chronic kidney disease (CKD) patients. The present study aimed to identify major independent risk factors and determine their contribution and relationship to LVH development.

Methods

Clinical and echocardiographic data of 2002 pre-dialytic CKD patients were retrospectively collected. Independent risk factors for LVH were identified using univariable and multivariable logistic regression. Nomograms together with restricted cubic splines method were employed to explore the effect size and possible non-linear relationship with regard to LVH. A simplified predictive model was constructed and its predictive ability was validated to demonstrate to which extent the identified risk factors accounted for LVH risk.

Results

Multivariable logistic regression identified age, body mass index (BMI), systolic blood pressure (SBP), eGFR and hemoglobin as independent influencing factors for LVH. Nomogram revealed BMI, SBP and hemoglobin concentration as the most important risk factors. Impaired renal function only showed obvious risk for LVH when eGFR declined below 30 ml/min/1.73 m². Significant threshold effects existed for blood pressure and obesity that the risks for LVH doubled when SBP exceeded 160 mmHg or BMI exceeded 30 kg/m². The predictive model constructed performed well on both the training and validation cohort using calibration curve, ROC curve and AUC value, with AUC above 0.80 for both the training cohort and the validation cohort.

Conclusions

With the help of nomogram model, we identified five independent factors that explain a large proportion of LVH risk in CKD patients. Among them, major contribution to LVH development was resulted from comorbidities and complications of CKD (hypertension, anemia, obesity) rather than eGFR reduction per se. Non-linear relationship and threshold relationship between eGFR, blood pressure, obesity and LVH risk were also identified.

A Bibliometric and Visualized Analysis of Uremic Cardiomyopathy From 1990 to 2021

Background

Uremic cardiomyopathy is commonly presented in chronic kidney disease (CKD), and it severely affects the prognosis of patients with CKD. In the past few decades, the investigation of uremic cardiomyopathy has developed rapidly. However, no report has summarized the situation of uremic cardiomyopathy research to date. This study aimed to evaluate the state of uremic cardiomyopathy research in the last 30 years and identify important topics and achievements, as well as emerging trends through bibliometric analysis.

Materials and Methods

Publications related to uremic cardiomyopathy were collected from Science Citation Index Expanded. HistCite, VOSviewer, CiteSpace, and the Bibliometrix Package were used for bibliometric analysis and visualization, including the analysis of the overall distribution of the annual publication, leading countries, and active institutions and authors, core journals, co-cited references, and keywords.

Results

A total of 2,403 studies related to uremic cardiomyopathy were obtained, and progress related to uremic cardiomyopathy was slower in past 3 years. A total of 10,077 authors from 2,697 institutions in 89 countries or regions reported investigations on uremic cardiomyopathy. The United States of America was the most productive and the most cited country. Myles Wolf, Joseph I Shapiro, and Carmine Zoccali published most articles in uremic cardiomyopathy, and journals in nephrology possessed core status in the field. Phosphate metabolism was the hotspot in uremic cardiomyopathy research in recent years, and future progress may concentrate on phosphate metabolism, endogenous natriuretic factors, and novel biomarkers.

Conclusion

The United States of America and European countries played central roles in uremic cardiomyopathy research, while Chinese scholars should be more involved in this field. Global publications on uremic cardiomyopathy have entered platform stage, and the fibroblast growth factor-23-klotho axis remained a hotspot in this field. Endogenous natriuretic factors and novel biomarkers may be potential directions in future investigations.

The Diabetic Cardiorenal Nexus

The end-stage of the clinical combination of heart failure and kidney disease has become known as cardiorenal syndrome. Adverse consequences related to diabetes, hyperlipidemia, obesity, hypertension and renal impairment on cardiovascular function, morbidity and mortality are well known. Guidelines for the treatment of these risk factors have led to the improved prognosis of patients with coronary artery disease and reduced ejection fraction. Heart failure hospital admissions and readmission often occur, however, in the presence of metabolic, renal dysfunction and relatively preserved systolic function. In this domain, few advances have been described. Diabetes, kidney and cardiac dysfunction act synergistically to magnify healthcare costs. Current therapy relies on improving hemodynamic factors destructive to both the heart and kidney. We consider that additional hemodynamic solutions may be limited without the use of animal models focusing on the cardiomyocyte, nephron and extracellular matrices. We review herein potential common pathophysiologic targets for treatment to prevent and ameliorate this syndrome.

Characterization of preoperative cardiovascular status and association with outcome following feline renal allograft transplantation: 166 cases

OBJECTIVES

To retrospectively evaluate preoperative historical, biochemical, and cardiovascular screening data for predictors of survival to discharge and long-term survival in feline renal allograft recipients from 1 institution.

ANIMALS

166 cats that underwent renal transplantation at the University of Pennsylvania between 1998 and 2018.

PROCEDURES

Medical records were reviewed for preoperative historical information, biochemical data, and cardiac assessment including auscultation findings, pre- and postoperative systolic blood pressure measurements, thoracic radiographic evaluation, and echocardiographic measurements. The need for hemodialysis, the number of surgical procedures, native kidney biopsy diagnosis and survival time was also recorded. Kaplan-Meier analysis was used to generate survival plots and estimate median survival times with a 95% CI. Univariable and multivariable analysis were performed to determine variables that were independently associated with survival to discharge and long-term survival.

RESULTS

The patient population primarily consisted of adult male DSH cats (70%) diagnosed with IRIS stage 4 CKD (66.3%). Abnormalities identified on preoperative cardiac assessment, including hypertension, the presence of a murmur, echocardiographic changes, and radiographic signs of congestive heart failure, were not associated with survival to discharge or long-term survival. Age was the only single significant variable associated with survival, and the risk of death increased by 11% (95% CI, 6% to 17%) for every 1 year in patient age.

CLINICAL RELEVANCE

The presence of cardiac abnormalities identified during the screening process of cats presenting for transplantation should not immediately exclude a potential candidate for the procedure. Owners considering transplantation should be educated on the impact of age on survival following surgery.

Artificial intelligence assessment for early detection and prediction of renal impairment using electrocardiography

Purpose

Although renal failure is a major healthcare burden globally and the cornerstone for preventing its irreversible progression is an early diagnosis, an adequate and noninvasive tool to screen renal impairment (RI) reliably and economically does not exist. We developed an interpretable deep learning model (DLM) using electrocardiography (ECG) and validated its performance.

Methods

This retrospective cohort study included two hospitals. We included 115,361 patients who had at least one ECG taken with an estimated glomerular filtration rate measurement within 30 min of the index ECG. A DLM was developed using 96,549 ECGs of 55,222 patients. The internal validation included 22,949 ECGs of 22,949 patients. Furthermore, we conducted an external validation with 37,190 ECGs of 37,190 patients from another hospital. The endpoint was to detect a moderate to severe RI (estimated glomerular filtration rate < 45 ml/min/1.73m²).

Results

The area under the receiver operating characteristic curve (AUC) of a DLM using a 12-lead ECG for detecting RI during the internal and external validation was 0.858 (95% confidence interval 0.851–0.866) and 0.906 (0.900–0.912), respectively. In the initial evaluation of 25,536 individuals without RI patients whose DLM was defined as having a higher risk had a significantly higher chance of developing RI than those in the low-risk group (17.2% vs. 2.4%, p < 0.001). The sensitivity map indicated that the DLM focused on the QRS complex and T-wave for detecting RI.

Conclusion

The DLM demonstrated high performance for RI detection and prediction using 12-, 6-, single-lead ECGs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11255-022-03165-w.

The value of ventricular gradient for predicting pulmonary hypertension and mortality in hemodialysis patients

Pulmonary hypertension (PHT) is associated with increased mortality in hemodialysis (HD) patients. The ventricular gradient optimized for right ventricular pressure overload (VG-RVPO) is sensitive to early changes in right ventricular overload. The study aimed to assess the ability of the VG-RVPO to detect PHT and predict all-cause and cardiac mortality in HD patients. 265 selected HD patients were enrolled. Clinical, biochemical, electrocardiographic, and echocardiographic parameters were evaluated. Patients were divided into normal and abnormal VG-RVPO groups, and were followed-up for 3 years. Abnormal VG-RVPO patients were more likely to be at high or intermediate risk for PHT, were older, had longer HD vintage, higher prevalence of myocardial infarction, higher parathormone levels, shorter pulmonary flow acceleration time, lower left ventricular ejection fraction, higher values of left atrial volume index, left ventricular mass index, and peak tricuspid regurgitant velocity. Both all-cause and CV mortality were higher in abnormal VG-RVPO group. In multivariate Cox analysis, VG-RVPO remained an independent and strong predictor of all-cause and CV mortality. In HD patients, abnormal VG-RVPO not only predicts PHT, but also all-cause and CV mortality.

Prolongation of QTc interval at the beginning and during dialysis is associated with hypervolemia and calcium and magnesium change in the first 2 h

BACKGROUND AND AIMS

High rates of sudden cardiac death are mostly attributed to ventricular arrhythmias including QTc prolongation in hemodialysis patients. We aimed to investigate the correlation of electrolyte and volume changes with QTc interval prolongation in hemodialysis patients.

STUDY DESIGN

The present study is designed as a cross-sectional study.

METHODS

The study was conducted at the hemodialysis unit of a training and research hospital and its' satellite dialysis unit. Patients were divided into three groups. Group-1: with normal QTc interval both at the beginning and during dialysis session; group-2: with prolonged QTc interval at the beginning and remained prolonged during dialysis session; group-3: with normal QTc interval at the beginning but prolonged during the dialysis session. In addition, patients were evaluated in terms of QTc change between the beginning and 2nd hour (delta-QTc-1) and between 2nd hour and 4th hour (delta-QTc-2), respectively, and defined as 'patients with increased QTc interval' and 'patients without increased QTc interval'.

RESULTS

A total of 45 prevalent hemodialysis patients were enrolled in the study. 14 patients (31.1%) had normal QTc interval (group-1), 13 patients (28.9%) had prolonged QTc interval at the beginning and remained prolonged during dialysis session (group-2) and 18 patients (40%) had normal QTc interval at the beginning but prolonged during dialysis session (group-3). There was no statistically significant difference between groups in terms of baseline electrolyte levels. Calcium change in the first 2 h was lower in patients with QTc prolongation from the start or during the dialysis session (group-2 and group-3). In addition, systolic blood pressure (SBP) levels at the beginning of the session (118 ± 15 mmHg vs 124 ± 28 mmHg vs138 ± 24 mmHg; p = 0.04) and intradialytic ultrafiltration (UF) rate were higher (1.96 ± 0.6 L/4 h vs 2.6 ± 1.0 L/4 h vs 2.8 ± 0.9 L/4 h; p = 0.03) in group-2 and group-3 compared to patients in group-1. Increase in QTc interval was found higher in patients with less calcium increase (Rho: - 0.36; p = 0.01) and with greater magnesium decrease in the first 2 h (Rho: 0.31; p = 0.04).

CONCLUSION

QTc interval prolongation is common among hemodialysis patients. High intradialytic UF rates, change in serum magnesium and calcium levels in the first 2 h were found associated with QTc prolongation. However, QTc prolongation was found independently associated only with UF volume and calcium change in the first 2 h.

Narrative Review of Carotid disease and the kidney

Patients with chronic kidney disease (CKD) have an increased cardiovascular (CV) risk that is only in part explained by established risk factors. Carotid arteriosclerosis and atherosclerosis are increased in CKD, play a role in the causation of CV disease in these patients and can affect the progression of renal disease. The arterial stiffening process is evident even in CKD patients with a very mild reduction of glomerular filtration rate (GFR) whereas arterial thickening is evident in more advanced stages. Possible mechanisms include functional and structural alterations of the arterial wall. Arterial stiffness can mediate the effect of CKD on target organs (i.e., brain, kidney and heart). In this review we discuss the arterial phenotype of patients with CKD. This is characterized by increased common carotid artery stiffness and outward remodeling (enlargement and thickening of the arterial wall) and a normal/reduced stiffness paired with an inward remodeling (narrowing of the arterial wall) of muscular arteries. We also discuss the consequences of carotid dysfunction, including the involvement of large elastic arteries stiffness on ventricular-vascular coupling, the mechanisms linking carotid stiffening and increased cardio- and cerebrovascular risk in CKD patients, and the therapeutic options to improve carotid function.

The cardiovascular-dialysis nexus: the transition to dialysis is a treacherous time for the heart

Chronic kidney disease (CKD) patients require dialysis to manage the progressive complications of uraemia. Yet, many physicians and patients do not recognize that dialysis initiation, although often necessary, subjects patients to substantial risk for cardiovascular (CV) death. While most recognize CV mortality risk approximately doubles with CKD the new data presented here show that this risk spikes to >20 times higher than the US population average at the initiation of chronic renal replacement therapy, and this elevated CV risk continues through the first 4 months of dialysis. Moreover, this peak reflects how dialysis itself changes the pathophysiology of CV disease and transforms its presentation, progression, and prognosis. This article reviews how dialysis initiation modifies the interpretation of circulating biomarkers, alters the accuracy of CV imaging, and worsens prognosis. We advocate a multidisciplinary approach and outline the issues practitioners should consider to optimize CV care for this unique and vulnerable population during a perilous passage.

The association of echocardiographic parameters on renal outcomes in chronic kidney disease

BACKGROUND

Patients with chronic kidney disease (CKD) often have structural abnormalities of the heart due to pressure and volume overload. The aim of this study was to evaluate associations between echocardiographic parameters and renal outcomes (estimated glomerular filtration rate [eGFR] slope and progression to dialysis) in patients with stage 3-5 CKD.

METHODS

This longitudinal study enrolled 419 patients. Changes in renal function were assessed using the eGFR slope. Rapid renal progression was defined as an eGFR slope < -3 mL/min/1.73 m²/year, and the renal endpoint was defined as commencing dialysis.

RESULTS

Increased left atrial diameter (LAD), ratio of left ventricular mass to body surface area (LVM/BSA), ratio of LVM to height^2.7 (LVM/ht^2.7), and ratio of observed to predicted LVM (o/p LVM) were associated with eGFR slope in an adjusted model, but left ventricular ejection fraction (LVEF) was not. Furthermore, LAD ≥ 4.7 cm, LVM/BSA > 115 g/m² in males and > 95 g/m² in females, and LVM/ht^2.7 > 48 g/ht^2.7 in males and > 44 g/ht^2.7 in females were correlated with progression to dialysis, but o/p LVM and LVEF were not. The maximum change in χ² change to predict renal outcomes was observed for LAD, followed by LVM/BSA and LVM/ht^2.7.

CONCLUSIONS

A large LAD and increased LVM, regardless of how it was measured (LVM/BSA, LVM/ht^2.7 and o/p LVM), were correlated with adverse renal outcomes in patients with CKD stage 3-5. LAD had superior prognostic value to LVM and LVEF.

Uraemic Cardiomyopathy: A Review of Current Literature

Uraemic Cardiomyopathy (UC) is recognised as an intricate and multifactorial disease which portends a significant burden in patients with End-Stage Renal Disease (ESRD). The cardiovascular morbidity and mortality associated with UC is significant and can be associated with the development of arrythmias, cardiac failure and sudden cardiac death (SCD). The pathophysiology of UC involves a complex interplay of traditional implicative factors such as haemodynamic overload and circulating uraemic toxins as well as our evolving understanding of the Chronic Kidney Disease-Mineral Bone Disease pathway. There is an instrumental role for multi-modality imaging in the diagnostic process; including transthoracic echocardiography and cardiac magnetic resonance imaging in identifying the hallmarks of left ventricular hypertrophy and myocardial fibrosis that characterise UC. The appropriate utilisation of the aforementioned diagnostics in the ESRD population may help guide therapeutic approaches, such as pharmacotherapy including beta-blockers and aldosterone-antagonists as well as haemodialysis and renal transplantation. Despite this, there remains limitations in effective therapeutic interventions for UC and ongoing research on a cellular level is vital in establishing further therapies.

QT Prolongation in Dialysis Patients: An Epidemiological Study with a Focus on Malnutrition

BACKGROUND/AIMS

QT prolongation is a known risk factor for ventricular fibrillation and ventricular tachycardia. Therefore, more refined management is necessary to reduce sudden cardiac death secondary to such arrhythmias.

METHODS

Electrocardiographic findings were reviewed in 224 patients, and the associations of QT prolongation with various clinical parameters were examined, including the nutritional state. Correlations were also examined between QT prolongation and body composition measurements determined by multifrequency bioelectrical impedance analysis.

RESULTS

Prolongation of the corrected QT (QTc) interval over 0.44 s was seen in 140 patients (62.5%). QT prolongation was independent of age and dialysis therapy duration and was more frequent in diabetics (70.1%) than in nondiabetics (54.2%, p = 0.014) and more frequent in women (78.8%) than in men (53.5%, p < 0.001). Serum levels of albumin (p < 0.001) and Cr (p < 0.001) and the Geriatric Nutritional Risk Index (GNRI, p < 0.001) were negatively correlated with QTc interval; no significant correlation was noted with total protein, urea nitrogen, or uric acid. Negative correlations with QTc interval were found for BMI(p < 0.01), percent total body water (%TBW; p < 0.05), and percent intracellular water (%ICW; p < 0.01) but not with the percent extracellular water/TBW ratio or edema ratio. The longer the QTc interval, the lower the fat-free mass (FFM; p < 0.01) and muscle mass (MM; p < 0.01), but there was no significant correlation with percent fat.

CONCLUSION

These results suggest that QT prolongation is a common complication and is more frequent in women and diabetic patients. The decreases in serum albumin and Cr levels, GNRI, BMI, %TBW, %ICW, FFM, and MM together coincided with malnutrition and thus suggest a close relationship of QT prolongation with malnutrition. Management of QT prolongation may be achieved better in the future by understanding these biochemical and biophysical changes, particularly those regarding malnutrition.

Prediction of All-Cause Mortality Using an Echocardiography-Based Risk Score in Hemodialysis Patients

AIM

To derive an echocardiography-based prognostic score for a 3-year risk of mortality in end-stage renal disease (ESRD) patients undergoing hemodialysis (HD).

METHODS

173 ESRD patients hospitalized in the second affiliated hospital of Soochow University from January 1, 2010, to July 31, 2016, were enrolled and followed up for 3 years. All subjects began to receive HD from recruitment. Baseline clinical and echocardiographic parameters were collected and screened for risk factors using univariate and multivariate analysis. The prognostic value of echocardiographic indexes was determined by concordance indexes and reclassification assay. Restricted cubic spline models (RCS) and forest plots were employed to visualize the association between risk factors and all-cause mortality. A multivariate nomogram including the identified factors was developed to estimate the prognosis.

RESULTS

After multivariate adjustment for advanced age, hypertension, diabetes, and decreased hemoglobin (Hb), echocardiographic indexes including left atrial diameter index (LADI), cardiac valvular calcification, and moderate to severe cardiac valve regurgitation were independently associated with the risk of 3-year mortality in HD patients. RCS showed that age, Hb, and LADI were positively associated with the risk of mortality. Adding multiple echocardiographic indexes to a basic model containing age, hypertension, diabetes, and Hb increased the concordance index and improved reclassification. A multivariate Cox model-derived nomogram showed the association between each factor and mortality by the end of follow-up.

CONCLUSIONS

Echocardiographic indexes showed independent predictive power for mortality in ESRD patients and may constitute a promising prognostic tool in this population.

Electrocardiographic abnormalities among late-stage non-dialysis chronic kidney disease patients

OBJECTIVES

Cardiovascular disease (CVD) complication is common among chronic kidney disease (CKD) patients. Thus, knowledge about CVD and ECG abnormalities in CKD are essential due to progressive nature of the disease and increased risk of sudden cardiac death. This study aims to scrutinize the ECG abnormalities among nondialysis late-stage CKD patients.

METHODS

A descriptive observational study was conducted at Dr. Soetomo General Hospital, Surabaya, Indonesia. Subjects were hospitalized patients with late-stage CKD between 1 January and 31 December 2019, who were consulted at the department of cardiology and vascular medicine during their initial admission at emergency room. ECG interpretation for this study was done by qualified cardiologist.

RESULTS

There were 191 patients included in this study. Mean ages were 52.2 ± 11.8 years old and 51% were males. Total 143 (74.9%) patients had anemia, 111 (58.1%) had hypertension and 75 (39.3%) had type 2 diabetes mellitus. Mean serum creatinine was 10.5 ± 8.0 mg/dL. There were 176 (92.1%) patients with at least one form of ECG abnormalities. Prolonged QTc interval (36.6%), fragmented QRS complex (29.8%), poor R wave progression (24.6%), peaked T wave (22.0%) and left ventricular hypertrophy (16.7%) were the most common abnormalities.

CONCLUSIONS

ECG abnormalities are common among nondialysis late-stage CKD patients. Given the fact that long-term CKD influences the pathogenesis cardiovascular diseases and substantial cardiovascular mortality, there is a need to screen Indonesian CKD patients who are at risks of getting earlier complications.

Adverse Drug Events in Patients with Chronic Kidney Disease Associated with Multiple Drug Interactions and Polypharmacy

BACKGROUND AND PURPOSE

Chronic kidney disease (CKD) is associated with adverse drug events due to medication errors and the risks of polypharmacy. The aim of this study was to investigate whether multiple pharmacodynamic interactions are a significant problem in CKD patients to improve medication safety.

METHODS

The discharge medication of 200 elderly patients with stage 3, 4 and 5/5D CKD was analysed in a retrospective observational study with respect to kidney-related medication errors and multiple pharmacodynamic interactions. The clinical relevance of the most common and hazardous multiple interactions was assessed by evaluating adverse events at the primary or the subsequent hospital stay.

RESULTS

Findings showed that 29.5% of the study cohort were at risk of QTc-interval prolongation in association with their medication combinations and half of them exhibited QTc-interval prolongation. The QTc interval was extended among all patients receiving a combination of two or more drugs with 'known' risk of Torsades de pointes. Amiodarone, citalopram and ciprofloxacin turned out to be the most hazardous drugs in this context. Eight percent of the patient population received a regimen of 4-6 potassium-enhancing drugs during their hospital stay, which was not de-escalated in 75.0% in the ambulatory setting. Despite close monitoring in the clinical setting, 37.5% of these patients developed hyperkalaemic episodes during their primary stay and 66.7% during rehospitalization. Of the study cohort, 8.5% received a combination of three drugs with antithrombotic or antiplatelet effects. Of these, 64.7% developed haemorrhagic events with two of them proving fatal.

CONCLUSION

Multiple pharmacodynamic interactions related to QTc prolongation, hyperkalaemia and haemorrhage are frequently associated with a negative outcome in older adults with CKD and often require recurrent medical treatment or rehospitalization.

Drug interactions and creatinine levels are associated with QTc prolongation in intensive care units: a prospective, observational study

Background Prolongation of the QTc interval may lead to life threatening arrhythmias. QTc prolongation is common in intensive care unit (ICU) patients. The objectives of this study were to identify the role of drug-drug interactions (DDIs) and other predictors (age, sex, cardiovascular diseases, and electrolyte abnormalities) in life threatening QTc prolongation in patients admitted to medical (M), surgical (S) and emergency (E) ICUs. Methods This prospective, observational study included patients above the age of 18 years who were admitted to SICU, EICU, and MICU at a tertiary respiratory referral center. Electrocardiogram (ECG) monitoring was performed during the first 5 days of ICU admission. Risk factors and DDIs which were anticipated to be associated with the prolongation of the QTc interval were assessed for all patients. Results Two hundred patients were included in the study. QTc prolongation occurred in 10.7% of patients and the majority of patients presenting with QTc prolongation had creatinine levels above 1.3 mg/dL during their 5 days of ICU admission. Incidence of pharmacodynamic (PD) DDIs was significantly higher in patients with QTc prolongation vs. other patients. Creatinine levels above 1.3 mg/dL and PD DDIs were associated with QTc prolongation during 5 days of ICU admission. Conclusions High serum creatinine and PD DDIs can increase the risk of QTc prolongation in patients admitted to the ICU. QTc interval measurements should be performed prior to initiation or after starting any drug that is associated with QT prolongation, specifically in patients with the known risk factors.

Assessment of right heart functions in the patients with arteriovenous fistula for hemodialysis access: Right ventricular free wall strain and tricuspid regurgitation jet velocity as the predictors of right heart failure

Objectives

Previous studies have mostly focused on the left-sided cardiovascular changes, but right-sided cardiac changes and predictive factors have not been examined in advance following arteriovenous fistula (AVF) creation. We aimed to identify new parameters which contribute to the prediction of right heart failure (RHF) after AVF creation.

Methods

The study cohort comprised 81 patients who underwent AVF creation between January 2014 and April 2019 in our center. The study cohort was divided into the patients with RHF ( n = 15, 18.5%) and without RHF ( n = 66, 72.5%) following AVF creation.

Results

Mean age of cohort was 49.9 ± 14.7 years (range 23–66) and 39 (48.1%) were men. Approximately 74.07% (60 patients) were in New York Heart Association Class II and III profile preoperatively. Independent predictors for RHF following AVF were right ventricle longitudinal strain (RVLS) free wall <-19% [odds ratio (OR) 2.31, 95% CI 1.02–3.22], and tricuspid regurgitation jet velocity (TRJV) >2.5 m/s [odds ratio (OR) 5.68, 95% CI 1.21–4.38]. Receiver operating characteristic analysis was performed with a resulting area under the curve value of 0.86 (95% CI 0.55–0.89, p = 0.004) for RVLS free wall <-14.2% and 0.81 for TRJV >2.61 m/s (95% CI 0.55–0.89, p = 0.005) in predicting RHF following AVF.

Conclusions

RVLS free wall <-14.2% and TRJV >2.61 m/s were independent predictors of RHF following AVF creation. The patients at risk for having RHF following AVF creation or who may benefit from AVF should be identified with predictive parameters and prospective clinical studies.

Echocardiographic assessment of cardiac structure and function in chronic renal disease

Chronic kidney disease (CKD) is a global health problem and is independently associated with increased risk for cardiovascular disease (CVD). The presence and severity of CKD is strongly related to the progression of coronary atherosclerosis, ventricular hypertrophy, myocardial fibrosis, valvular calcification, and cardiac conduction system abnormalities. Echocardiography plays a major role in the assessment of structural and functional cardiac abnormalities in CKD including abnormal left-ventricular (LV) geometry, LV diastolic dysfunction, valvular disease, and left atrial dilatation, which are very frequently present especially in patients with end-stage renal disease.

Polycystin-1 Assembles With Kv Channels to Govern Cardiomyocyte Repolarization and Contractility

BACKGROUND

Polycystin-1 (PC1) is a transmembrane protein originally identified in autosomal dominant polycystic kidney disease where it regulates the calcium-permeant cation channel polycystin-2. Autosomal dominant polycystic kidney disease patients develop renal failure, hypertension, left ventricular hypertrophy, and diastolic dysfunction, among other cardiovascular disorders. These individuals harbor PC1 loss-of-function mutations in their cardiomyocytes, but the functional consequences are unknown. PC1 is ubiquitously expressed, and its experimental ablation in cardiomyocyte-specific knockout mice reduces contractile function. Here, we set out to determine the pathophysiological role of PC1 in cardiomyocytes.

METHODS

Wild-type and cardiomyocyte-specific PC1 knockout mice were analyzed by echocardiography. Excitation-contraction coupling was assessed in isolated cardiomyocytes and human embryonic stem cell-derived cardiomyocytes, and functional consequences were explored in heterologous expression systems. Protein-protein interactions were analyzed biochemically and by means of ab initio calculations.

RESULTS

PC1 ablation reduced action potential duration in cardiomyocytes, decreased Ca²⁺ transients, and myocyte contractility. PC1-deficient cardiomyocytes manifested a reduction in sarcoendoplasmic reticulum Ca²⁺ stores attributable to a reduced action potential duration and sarcoendoplasmic reticulum Ca²⁺ ATPase (SERCA) activity. An increase in outward K⁺ currents decreased action potential duration in cardiomyocytes lacking PC1. Overexpression of full-length PC1 in HEK293 cells significantly reduced the current density of heterologously expressed Kv4.3, Kv1.5 and Kv2.1 potassium channels. PC1 C terminus inhibited Kv4.3 currents to the same degree as full-length PC1. Additionally, PC1 coimmunoprecipitated with Kv4.3, and a modeled PC1 C-terminal structure suggested the existence of 2 docking sites for PC1 within the N terminus of Kv4.3, supporting a physical interaction. Finally, a naturally occurring human mutant PC1^R4228X manifested no suppressive effects on Kv4.3 channel activity.

CONCLUSIONS

Our findings uncover a role for PC1 in regulating multiple Kv channels, governing membrane repolarization and alterations in SERCA activity that reduce cardiomyocyte contractility.

Early Effects of Renal Replacement Therapy on Cardiovascular Comorbidity in Children With End-Stage Kidney Disease: Findings From the 4C-T Study

BACKGROUND

The early impact of renal transplantation on subclinical cardiovascular measures in pediatric patients has not been widely investigated. This analysis is performed for pediatric patients participating in the prospective cardiovascular comorbidity in children with chronic kidney disease study and focuses on the early effects of renal replacement therapy (RRT) modality on cardiovascular comorbidity in patients receiving a preemptive transplant or started on dialysis.

METHODS

We compared measures indicating subclinical cardiovascular organ damage (aortal pulse wave velocity, carotid intima media thickness, left ventricular mass index) and evaluated cardiovascular risk factors in 166 pediatric patients before and 6 to 18 months after start of RRT (n = 76 transplantation, n = 90 dialysis).

RESULTS

RRT modality had a significant impact on the change in arterial structure and function: compared to dialysis treatment, transplantation was independently associated with decreases in pulse wave velocity (ß = -0.67; P < 0.001) and intima media thickness (ß = -0.40; P = 0.008). Independent of RRT modality, an increase in pulse wave velocity was associated with an increase in diastolic blood pressure (ß = 0.31; P < 0.001). Increasing intima media thickness was associated with a larger increase in body mass index (ß = 0.26; P = 0.003) and the use of antihypertensive agents after RRT (ß = 0.41; P = 0.007). Changes in left ventricular mass index were associated with changes in systolic blood pressure (ß = 1.47; P = 0.01).

CONCLUSIONS

In comparison with initiating dialysis, preemptive transplantation prevented further deterioration of the subclinical vascular organ damage early after transplantation. Classic cardiovascular risk factors, such as hypertension and obesity are of major importance for the development of cardiovascular organ damage after renal transplantation.

Study of Echocardiographic Changes After Kidney Transplantation in End-stage Renal Disease Patients

Background

Cardiovascular complications are the leading cause of mortality in end-stage renal disease (ESRD) patients. This study aimed to evaluate the efficacy of kidney transplantation on the cardiovascular status in ESRD patients.

Methods

During 2012 to 2014 and in a cross-sectional study, 181 patients were randomly selected for this study. All patients were followed for periods of 6 and 12 months after kidney transplantation. The patients with ESRD and kidney transplant recipients; the patients with left ventricle ejection fraction<50%, left ventricular hypertrophy, mitral valve regurgitation and tricuspid valve regurgitation were included to study and the patients with kidney transplant rejection, myocardial infarction, high blood pressure with treatment-resistant, high blood pressure and addicted patients were censored.

Results

one hundred and eighty-one patients had the mean age of 38.52 (range, 16-69 years) that 54.7% were men and the mean duration of dialysis was 3.74 years. There were significant differences after 6 and 12 months compared with before and also 6 months compared with 12 months from kidney transplantation for all echocardiographic findings. The echocardiographic findings improved after 12 months compared with 6 months and also these times compared with before kidney transplantation.

Conclusions

The results of this study appeared that kidney transplantation had a positive effect on the cardiovascular status of patients with ESRD and improved the cardiac function of these patients.

Working Toward an Improved Understanding of Chronic Cardiorenal Syndrome Type 4

Chronic diseases of the heart and of the kidneys commonly coexist in individuals. Certainly combined and persistent heart and kidney failure can arise from a common pathologic insult, for example, as a consequence of poorly controlled hypertension or of severe diffuse arterial disease. However, strong evidence is emerging to suggest that cross talk exists between the heart and the kidney. Independent processes are set in motion when kidney function is chronically diminished, and these processes can have distinct adverse effects on the heart. The complex chronic heart condition that results from chronic kidney disease (CKD) has been termed cardiorenal syndrome type 4. This review will include an updated description of the cardiac morphology in patients who have CKD, an overview of the most likely CKD-sourced culprits for these cardiac changes, and the potential therapeutic strategies to limit cardiac complications in patients who have CKD.

Practice patterns in transitioning patients from chronic kidney disease to dialysis: a survey of United States nephrologists

Background

There are no guidelines for transitioning patients from chronic kidney disease stage 5 to hemodialysis. We conducted this study to determine if there are uniform patterns in how nephrologists transition patients to dialysis.

Methods

We designed an electronic survey with 39 questions and sent it to a database of practicing nephrologists at the National Kidney Foundation. Factors that were important for transitioning a patient to hemodialysis were evaluated, including medication changes on dialysis initiation, dry weight and dialysis prescription.

Results

160 US Nephrologists replied to the survey; 18% (29/160) of the responses were completed via social media sites. Prior to dialysis, 74% (118/160), prescribed furosemide and 67% (107/160) used furosemide with metolazone. Once dialysis started, only 46% (74/160) of the responders continued patients on diuretics daily. Hypertension medications prescribed in dialysis were calcium channel blockers 69% (112/160), beta blockers 36% (58/160), angiotensin converting enzyme inhibitor 32% (53/160), angiotensin receptor blocker 29% (46/160) and diuretics 25% (42/160). Once dialysis started, 68% (109/160) routinely changed medications. Most, 67% (107/160) ordered patients to avoid anti-hypertensive medications on dialysis days to allow for ultrafiltration. Dry weight was determined in the first week by 29% (46/160) and in the first month by 53% (85/160). Most, 59% (94/160) felt that multiple causes lead to hypertension. Most nephrologists would prescribe small dialyzers and a shorter period of time for the first dialysis session.

Conclusion

The transition period to chronic hemodialysis has variations in practice patterns and may benefit from further studies to optimize clinical practice.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-0943-0) contains supplementary material, which is available to authorized users.

Factors influencing P terminal force in lead V1 of the ECG in hemodialysis patients

INTRODUCTION

Atrial fibrillation (AF) is a highly prevalent arrhythmia in hemodialysis (HD) patients, and an HD session may be a trigger for AF episodes. An abnormal P-terminal force in lead V1 (PTFV1) may predict new-onset AF in HD patients. The aim of the study was to assess the influence of the HD process on PTFV1 and to evaluate possible factors influencing PTFV1 in a group of selected HD patients.

MATERIAL AND METHODS

One hundred and fifty-three selected HD patients entered the study. Blood chemistry, electrocardiography, and impedance cardiography were evaluated before and after HD. Echocardiography was performed on the morning after dialysis. Abnormal PTFV1 was defined as PTFV1 > 40 mm × ms.

RESULTS

Abnormal PTFV1 was found in 35.3% of patients before dialysis and in 48.4% of patients after dialysis. The results of multiple regression analysis revealed that the independent predictors of pre-dialysis abnormal PTFV1 were: left atrial volume index (p = 0.002), left ventricular mass index (p = 0.014), and pre-dialysis thoracic fluid content (p = 0.021) values. The independent predictors of HD-induced abnormal PTFV1 values were larger differences between pre-dialysis and post-dialysis values of serum potassium (p < 0.001) and mean arterial pressure (p = 0.008).

CONCLUSIONS

Abnormal PTFV1 is prevalent in HD patients. The HD process adversely affects PTFV1 values. Pre-dialysis abnormal PTFV1 is mainly associated with structural heart abnormalities and hydration status. HD-induced abnormal PTFV1 is associated predominantly with serum potassium changes as well as HD-induced hypotension. Our results suggest possible risk factors for AF; however, their clinical significance needs to be confirmed in follow-up studies.

Type 2 diabetes mellitus-related changes in left ventricular structure and function in patients with chronic kidney disease

Type 2 Diabetes mellitus (DM) is the leading cause of chronic kidney disease (CKD) worldwide, and is associated with an increased risk of left ventricular (LV) hypertrophy, LV systolic and diastolic dysfunctions. The aim of this study was to investigate abnormal echocardiographic findings in patients with CKD with and without DM, and identify the factors associated with these abnormalities. We enrolled 356 pre-dialysis patients with CKD (stages 3-5), including 208 with DM and 148 without DM. The structure and systolic and diastolic functions of the left ventricle were assessed using echocardiography, and the clinical and echocardiographic parameters were analyzed. The patients with DM had higher rates of observed/predicted left ventricular mass > 128% (69.5% vs. 56.7%, p = 0.015), midwall fractional shortening < 14% (22.6% vs. 8.8%, p = 0.001), and ratio of peak early transmitral filling wave velocity to early diastolic velocity of lateral mitral annulus > 12 (32.7% vs. 16.2%, p < 0.001) than those without DM. Multivariate analysis showed that male sex, a history of smoking, high systolic blood pressure, high body mass index, high levels of fasting glucose and total cholesterol, low levels of albumin and hemoglobin, and a low estimated glomerular filtration rate were associated with abnormal echocardiographic findings. The rates of inappropriate left ventricular mass, systolic and diastolic dysfunction were higher in our patients with CKD and DM than in those without DM.

Left ventricular hypertrophy among chronic kidney disease patients in Ghana

Introduction

The presence of left ventricular hypertrophy (LVH) in patients with Chronic Kidney Disease (CKD) is associated with worsening cardiovascular outcomes. There is a dearth of data on LVH in Ghanaian CKD patients.

Methods

This was a cross sectional study carried out at the Komfo Anokye Teaching Hospital (KATH) in Kumasi, Ghana. A questionnaire was used to obtain information on clinical features of CKD. The MDRD-4 equation was used to calculate eGFR. Information on the prevalence and factors associated with electrocardiographic left ventricular hypertrophy were obtained during the initial assessment.

Results

About 64.5% of the 203 participants were male and the mean age was 43.9 ± 17.8 years. Most subjects (79.8%) had stage 5 disease. The mean systolic and diastolic blood pressures were 167.86 ± 39.87 and 101.8 ± 24.4 respectively. Approximately 43% of respondents had LVH. eGFR correlated negatively with LVH. High systolic pressure (OR 4.9, CI 2.4 – 10.4; p < 0.05), high diastolic pressure (OR 8.1, CI 4.0 – 16.1; p < 0.05) increased pulse pressure (OR 3.4 CI 2.6-9.3, p < 0.05), increased body mass index (OR 3.6 CI 1.7-11.2, p < 0.001) as well as male gender (OR 4.7, 95% CI 2.4 – 9.1; p <0.05) were associated with the presence of LVH.

Conclusion

LVH is common in our cohort. High pulse pressure, high DBP, increased BMI and male gender are significant associated factors. Adequate treatment of high blood pressure as well as early detection of LVH and interventions aimed at prevention and/or regression of LVH are to be encouraged.

Association of type 2 diabetes mellitus and ratio of transmitral E wave velocity to early diastole mitral velocity with cardiovascular events in chronic kidney disease

The association between DM and left ventricular diastolic dysfunction, assessed using the ratio of peak early transmitral filling wave velocity (E) to early diastolic velocity of mitral annulus (Ea), with cardiovascular (CV) outcomes in patients with chronic kidney disease (CKD) remains uncertain. This study included 356 CKD stage 3–5 patients underwent echocardiography. All patients were classified into four groups based on the presence of DM and E/Ea ≤ or > 9. CV events included CV death, hospitalization for heart failure, unstable angina or nonfatal myocardial infarction, sustained ventricular arrhythmia, transient ischemic attack, and stroke. There were 58 CV events during the mean observation period of 25.0 months. A combination of the presence of DM and E/Ea > 9 (vs. a combination of non-DM and E/Ea ≤ 9) was associated with CV events in unadjusted model (hazard ratio [HR], 6.990; 95% confidence interval [CI], 2.753–17.744; p < 0.001), and in a multivariate adjusted model (HR, 3.037; 95% CI, 2.088–7.177; p = 0.025). In the patients without DM, the E/Ea ratio (p = 0.033) improved the prediction of CV events, compared to the E/Ea ratio (p = 0.018), left atrial diameter (p = 0.016) and left ventricular mass index (p = 0.001) in the patients with DM. The combination of DM and left ventricular diastolic dysfunction was associated with CV events in patients with CKD stage 3–5. Assessments of DM status and E/Ea ratio may facilitate identifying high-risk patient population of unfavorable CV outcomes.

Reproducibility and Reliability Of QTc and QTcd Measurements and Their Relationships with Left Ventricular Hypertrophy in Hemodialysis Patients

Background

Left ventricular hypertrophy (LVH) is very common in hemodialysis patients and an independent risk factor for mortality in this population. The myocardial remodeling underlying the LVH can affect ventricular repolarization causing abnormalities in QT interval.

Objective

to evaluate the reproducibility and reliability of measurements of corrected QT interval (QTc) and its dispersion (QTcd) and correlate these parameters with LVH in hemodialysis patients.

Methods

Case-control study involving hemodialysis patients and a control group. Clinical examination, blood sampling, transthoracic echocardiogram, and electrocardiogram were performed. Intra- and interobserver correlation and concordance tests were performed by Pearson´s correlation, Cohen’s Kappa coefficient and Bland Altman diagram. Linear regression was used to analyze association of QTc or QTcd with HVE.

Results

Forty-one HD patients and 37 controls concluded the study. Hemodialysis patients tended to have higher values of QTc, QTcd and left ventricular mass index (LVMi) than controls but statistical significance was not found. Correlation and concordance tests depicted better results for QTc than for QTcd. In HD patients, a poor but significant correlation was found between QTc and LVMi (R² = 0.12; p = 0.03). No correlation was found between values of QTcd and LVMi (R²= 0.00; p=0.940). For the control group, the correspondent values were R²= 0.00; p = 0.67 and R²= 0.00; p = 0.94, respectively.

Conclusion

We found that QTc interval, in contrast to QTcd, is a reproducible and reliable measure and had a weak but positive correlation with LVMi in HD patients.

Impact of drugs on intradialytic hypotension: Antihypertensives and vasoconstrictors

Intradialytic hypotension (IDH) is a common complication of hemodialysis and is associated with numerous adverse outcomes including cardiovascular events, inadequate dialysis, loss of vascular access, and death. It is estimated that approximately 20%-30% of all dialysis sessions are affected by IDH. In seeking ways to reduce the occurrence of IDH, dialysis providers often turn to pharmacological approaches: withholding antihypertensive medications prior to hemodialysis or administering vasoconstrictor medications. This review will focus on what is known about the relation between antihypertensive medications and IDH, and summarize studies that have examined the efficacy of vasoconstrictor medications on IDH, including midodrine, arginine vasopressin, and droxidopa. However, there is currently scant evidence that any pharmacological approach is particularly effective in reducing IDH. Additional studies of potential treatments for IDH are needed, and should examine not only hemodynamic effects such as changes in nadir blood pressure during dialysis, but also on patient-centered and clinical outcomes such as symptoms of IDH, quality of life, and cardiovascular events.

Modern peptide biomarkers and echocardiography in cardiac healthy haemodialysis patients

BACKGROUND

In this prospective study, we aimed to assess the haemodynamic changes before and after haemodialysis (HD) in cardiac healthy subjects on chronic HD by imaging methods and endocrine markers of fluid balance.

METHODS

Mid-regional pro-atrial natriuretic peptide (MR-proANP), N-terminal prohormone of brain natriuretic peptide (NT-proBNP), vasopressin (AVP) and copeptin (CT-proAVP), metanephrines and normetanephrines, renin and aldosterone, standard transthoracic echocardiography and diameter of vena cava inferior (VCID) were performed in 20 patients with end stage renal disease (CKD5D) before and after HD and were stratified in residual excretion (RE, less or more 0.5 l) and ultrafiltration rate (UF, less or more 2 l).

RESULTS

Copeptin was significantly higher in patients before HD. Copeptin was inversely correlated with haemodialysis treatment adequacy (KT/v), RE and UF, but was not significantly influenced by age, gender and body mass index (BMI). MR-proANP was significantly reduced by haemodialysis by 27% and was inversely correlated with KT/v, but there was a significant influence by UF, RE, age, gender and BMI. NT-proBNP was significantly higher in patients before HD and was not influenced by RE and UF. Renin, aldosterone, metanephrines and normetanephrines did not demonstrate significant differences. Echocardiographic parameters and VCID were significantly correlated with RE, UF and copeptin.

CONCLUSION

Modern biomarkers will provide cardiovascular risk assessment, but elimination (UF), RE and other factors may influence the serum concentrations, e.g. in patients with renal impairment. The interpretation will be limited by altered reference ranges, and will be restricted to individual courses combined with clinical and echocardiographic data.

Echocardiographic assessment in patients with chronic kidney disease: Current update

Patients with chronic kidney disease (CKD) carry a high cardiovascular risk. An abundance of evidence has emerged in recent years establishing minor reductions in estimated glomerular filtration rate as an independent risk factor for cardiovascular mortality. Additionally, cardiac changes, such as left ventricular hypertrophy and impaired left ventricular systolic function, have been associated with an unfavorable prognosis. Despite the significant prevalence of underlying cardiac abnormalities, symptoms may not manifest in many patients with CKD. A range of available and emerging echocardiographic modalities may assist with diagnosing heart disease in CKD. Furthermore, some of these emerging techniques can give an important insight into the pathophysiology of subclinical dysfunction in CKD. This review discusses how current and emerging echocardiographic modalities such as speckle tracking echocardiography and 3D echocardiography might help cardiologists in providing important information to help with diagnosis and risk stratification of cardiac-related morbidity and mortality in patients with renal disease, as well applicability of these tools to current clinical practice.

Clearance of cardiovascular medications during hemodialysis

PURPOSE OF REVIEW

To review the current understanding of hemodialysis-mediated clearance of commonly used cardiovascular medications.

RECENT FINDINGS

Although cardiovascular drug dialyzability is poorly understood, many drug classes appear to include agents with substantially different degrees of dialyzability. Recent data suggest that more readily dialyzable beta-blockers associate with higher short-term mortality in patients initiating these drugs when on hemodialysis. Although this relationship was not observed in a later study with angiotensin-converting enzyme inhibitors of varying dialyzability, studies of this kind are currently limited by pharmacokinetic data that are either incomplete or no longer applicable to modern hemodialysis procedures.

SUMMARY

There are substantial deficits in our understanding of cardiovascular medication dialyzability, which relates in large part to advances in the process of hemodialysis that have rendered older studies of dialyzability irrelevant. The importance of cardiovascular disease in patients receiving hemodialysis demands a better understanding of the effect hemodialysis exerts on cardiovascular drug pharmacokinetics.

Cardiac Hepcidin Expression Associates with Injury Independent of Iron

BACKGROUND

Hepcidin regulates systemic iron homeostasis by downregulating the iron exporter ferroportin. Circulating hepcidin is mainly derived from the liver but hepcidin is also produced in the heart. We studied the differential and local regulation of hepcidin gene expression in response to myocardial infarction (MI) and/or chronic kidney disease (CKD). We hypothesized that cardiac hepcidin gene expression is induced by and regulated to severity of cardiac injury, either through direct (MI) or remote (CKD) stimuli, as well as through increased local iron content.

METHODS

Nine weeks after subtotal nephrectomy (SNX) or sham surgery (CON), rats were subjected to coronary ligation (CL) or sham surgery to realize 4 groups: CON, SNX, CL and SNX + CL. In week 16, the gene expression of hepcidin, iron and damage markers in cardiac and liver tissues was assessed by quantitative polymerase chain reaction and ferritin protein expression was studied by immunohistochemistry.

RESULTS

Cardiac hepcidin messenger RNA (mRNA) expression was increased 2-fold in CL (p = 0.03) and 3-fold in SNX (p = 0.01). Cardiac ferritin staining was not different among groups. Cardiac hepcidin mRNA expression correlated with mRNA expression levels of brain natriuretic peptide (β = 0.734, p < 0.001) and connective tissue growth factor (β = 0.431, p = 0.02). In contrast, liver hepcidin expression was unaffected by SNX and CL alone, while it had decreased 50% in SNX + CL (p < 0.05). Hepatic ferritin immunostaining was not different among groups.

CONCLUSIONS

Our data indicate differences in hepcidin regulation in liver and heart and suggest a role for injury rather than iron as the driving force for cardiac hepcidin expression in renocardiac failure.

Syndecan-4 Is an Independent Predictor of All-Cause as Well as Cardiovascular Mortality in Hemodialysis Patients

Background

Left ventricular hypertrophy is associated withincreased mortality in hemodialysis (HD) patients.Syndecan-4 plays a role in many processes that are involved in the heart fibrosis and hypertrophy.We designed this study to prospectively determine whether syndecan-4 was predictive of mortality in a group of HD patients.

Methods

In total, 191 HD patients were included. Clinical, biochemical and echocardiographic parameters were recorded. HD patients were followed-up for 23.18 ± 4.02 months.

Results

Syndecan-4 levels correlated strongly with geometrical echocardiographic parameters and ejection fraction. Relations with pressure-related parameters were weak and only marginally significant. Using the receiver operating characteristics the optimal cut-off points in predicting all-cause as well as cardiovascular (CV) mortality were evaluated and patients were divided into low and high syndecan-4 groups. A Kaplan–Meier analysis showed that the cumulative incidences of all-cause as well as CV mortality were higher in high serum syndecan-4 group compared with those with low serum syndecan-4 (p<0.001 in both cases).A multivariate Cox proportional hazards regression analysis revealed syndecan-4 concentration to be an independent and significant predictor of all-cause (hazard ratio, 2.99; confidence interval, 2.34 to 3.113; p<0.001)as well as CV mortality (hazard ratio, 2.81;confidence interval, 2.28to3.02; p<0.001).

Conclusions

Serum syndecan-4 concentration reflects predominantly geometrical echocardiographic parameters. In HD patients serum syndecan-4 concentration is independently associated with all-cause as well as CV mortality.

Electrocardiographic predictors of mortality and sudden cardiac death in patients with end stage renal disease on hemodialysis

Patients with end stage renal disease (ESRD) on hemodialysis experience a high incidence of cardiovascular mortality, and sudden cardiac death (SCD) accounts for approximately 25% of all deaths in this patient population. Despite this high risk of SCD, many non-invasive SCD risk stratification tools that are frequently applied to other patient populations (such as those with prior myocardial infarction and reduced left ventricular systolic function) may be less useful markers of increased SCD risk in ESRD. Improved SCD risk stratification tools for use specifically in patients on hemodialysis are therefore necessary to optimally target use of primary prevention interventions aimed at decreasing SCD incidence. Electrocardiography is an effective, non-invasive SCD risk stratification tool in hemodialysis patients. This article reviews data supporting the association between various ECG parameters (QT interval, spatial QRS-T angle, signal averaged ECG, heart rate variability, and T-wave alternans) and mortality/SCD in the dialysis population. Despite the association between abnormal ECG parameters and SCD, it remains unclear if these abnormal parameters (such as prolonged QT interval) are mechanistically related to SCD and/or ventricular arrhythmias, or if they are simply markers for more severe cardiac disease, such as left ventricular hypertrophy, that may independently predispose to SCD. Current obstacles that impair widespread implementation of ECG risk stratification in the hemodialysis population are also discussed.