Oxygen venous saturation is associated with subclinical myocardial systolic dysfunction in patients with end-stage renal disease undergoing hemodialysis

Introduction

The aim of this prospective study was to evaluate the impact of hemodialysis (HD) on myocardial injury, of both right and left ventricle function as well as their association with venous oxygen saturation (ScvO2) alterations.

Material and methods

We included in the study stable consecutive patients with end-stage renal disease (ESRD) undergoing regular HD. Right and left ventricular speckle-tracking echocardiographies were performed in all patients. The examination calculates the global systolic longitudinal strain (GLS). Blood samples were obtained from the central vein in order to measure the O2 saturation (ScvO2) levels prior and post HD. High sensitive troponin (HST) was also measured in all patients before and after HD.

Results

Thirty seven patients were evaluated. We found that both mean ScvO2 and left ventricle GLS (LV GLS) were deteriorated after the dialysis session: 76.47 ±1.98 to 71.54 ±5.10, p < 0.05 and -17.73 ±3.44 to -14.21 ±3.44%, p < 0.01, respectively. HST levels were increased at the end of hemodialysis, 22.45 ±13.26 to 106.78 ±146.19 pg/ml, p < 0.01. A significant correlation was also found between the decrease of LV GLS with the ScvO2 reduction, p = 0.001, as well as with the increase of the HST levels, p = 0.001.

Conclusions

Our data demonstrate that there is a significant worsening of the GLS of the left ventricle at the end of the dialysis, which is strongly associated with the concomitant deterioration of ScvO2. The may be a reliable index of circulatory stress indicating a subclinical myocardial dysfunction during HD.

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.

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.

Left Ventricular Mass and Functions in Egyptian Children with Chronic Kidney Disease in Comparison to Normal Subjects

Left ventricular hypertrophy (LVH) and cardiac fibrosis are common accompaniments of chronic kidney disease (CKD). They can be rather easily assessed by conventional cardiac imaging modalities, most practically by M-mode or two-dimensional (2D) echocardiography, with adequate recognition of pitfalls. This study uncovers the impact of impaired renal function on left ventricular mass (LVM) and LVM index (LVMI) in children with CKD on regular hemodialysis (HD) attending the Zagazig University Hospital for Children. A total of 80 Egyptian children, out of which 40 subjects having a mean age of 11.2 ± 3.12 years were cases with CKD in stage 5 on regular HD and the other 40 healthy subjects as controls, with a mean age of 12.2 ± 2.54 years, were included in the study and assessed for LVH and LVMI by 2D echocardiography. HD children had a significantly higher mean LVMI (102.3 ± 19.1 vs. 49.6 ± 4.11 g/m², P <0.001) than controls. Relative wall thickness was significantly higher in the patients with CKD patients on HD compared with controls (P <0.001) with a mean value of 0.46 indicating concentric LVH in renal patients. Comparing mitral inflow velocities between both the groups revealed that the patient group had a significant decrease in mitral E-wave velocity (0.88 ± 0.2 vs. 1.1 ± 0.1 m/sec, P <0.001) and E/A velocity ratio (1.3 ± 0.3 vs. 1.7 ± 0.3, P <0.001) in comparison with the control group, but there was no statistically significant difference in A-wave velocity. This indicates early diastolic dysfunction in CKD patients. LV mass changes in CKD children were strongly related to hypocalcemia and Vitamin D deficiency. Children with CKD are prone to the development of cardiac diastolic dysfunction and LVH, so early and regular echocardiographic studies of all children with CKD are recommended to detect early cardiac changes and institute interventions.

Association Between Nocturnal Blood Pressure Dipping and Chronic Kidney Disease Among Patients With Controlled Office Blood Pressure

BACKGROUND

Although abnormal blood pressure (BP) patterns are associated with adverse cardiorenal outcomes, their associations are yet unquantified by nocturnal dipping status. We examined the association of nocturnal BP dipping pattern with albuminuria and kidney function among participants with controlled hypertension without prior advanced kidney disease.

METHODS

Ambulatory BP (ABP) measurements were collected from 995 middle-aged, cardiology clinic patients with controlled office BP (OBP) (<140/90 mm Hg). The magnitude of dipping was calculated as the difference between daytime and nighttime systolic BP (SBP) divided by daytime SBP. Accordingly, the participants were categorized as extreme-dipper (≥20%), dipper (10% to <20%), non-dipper (0% to <10%), or reverse-dipper (<0%). We analyzed the cross-sectional associations of dipping with albuminuria (urine albumin-to-creatinine ratio ≥30 mg/g) and decreased estimated glomerular filtration rate (<60 ml/min/1.73 m2), adjusting for OBP/ABP, antihypertensive class, body mass index, total cholesterol, fasting glucose, socioeconomic status, and health behavior.

RESULTS

The participants (mean age 60.2 years; 52.9% male) consisted of 13.5% extreme-dippers, 43.1% dippers, 34.7% non-dippers, and 8.7% reverse-dippers. In reference to dippers, odds ratios [95% confidence interval] for albuminuria were 1.73 [1.04-2.60] in reverse-dippers, 1.67 [1.20-2.32] in non-dippers, and 0.62 [0.38-1.04] in extreme-dippers. Likewise, abnormal dipping profile was associated with decreased kidney function: reverse-dipping, 2.02 [1.06-3.84]; non-dipping, 1.98 [1.07-3.08]; extreme-dipping, 0.69 [0.20-1.17]. The associations persisted among participants with more conservatively controlled OBP (<130/80 mm Hg).

CONCLUSIONS

Monitoring diurnal and nocturnal BP may identify chronic kidney disease otherwise overlooked based on OBP.

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.

Five-year Outcomes of Pulmonary Hypertension With and Without Elevated Left Atrial Pressure in Patients Evaluated for Kidney Transplantation

BACKGROUND

Pulmonary hypertension (PH) is frequently reported in patients with advanced chronic kidney disease and is associated with early allograft failure and death. However, the causes of PH are heterogeneous, and patient prognosis may vary by etiologic subtype.

METHODS

Data from the University of North Carolina Cardiorenal Registry were examined to determine associations between PH, with or without elevated left atrial pressure (eLAP), and mortality in candidates for kidney transplantation. PH and eLAP were determined by Doppler echocardiography and by tissue Doppler imaging, respectively.

RESULTS

From 2006 to 2013, 778 registry patients were screened preoperatively by echocardiography. Most patients were black (64%) and men (56%); the mean age was 56 years. PH was identified in 97 (12%) patients; of these, eLAP was prevalent in half. During a median follow-up of 4.4 years, 179 (23%) received a kidney transplant, and 195 (25%) died. After adjustments for demographics, comorbidities, dialysis vintage, and kidney transplantation, PH was associated with twice the 5-year mortality (hazard ratio [HR] = 2.11; 95% confidence interval [CI]: 1.48-3.03), with stronger associations in the absence of eLAP (HR = 2.87; 95% CI: 1.83-4.49) than with eLAP (HR = 1.11; 95% CI: 0.57-2.17), P for interaction = 0.01.

CONCLUSIONS

The mortality risk associated with PH among patients with advanced chronic kidney disease appears to differ by etiology. Patients with PH in the absence of eLAP are at high risk of death and in need of focused attention. Future research efforts should investigate potential strategies to improve outcomes for these patients.

Heterogeneity of Effect of Net Ultrafiltration Rate among Critically Ill Adults Receiving Continuous Renal Replacement Therapy

INTRODUCTION

In continuous renal replacement therapy (CRRT)-treated patients, a net ultrafiltration (NUF) rate >1.75 mL/kg/h has been associated with increased mortality. However, there may be heterogeneity of effect of NUF rate on mortality, according to patient characteristics.

METHODS

To investigate the presence and impact of heterogeneity of effect, we performed a secondary analysis of the "Randomized Evaluation of Normal versus Augmented Level of Renal Replacement Therapy" (RENAL) trial. Exposure was NUF rate (weight-adjusted fluid volume removed per hour) stratified into tertiles (<1.01 mL/kg/h; 1.01-1.75 mL/kg/h; or >1.75 mL/kg/h). Primary outcome was 90-day mortality. Patients were clustered according to baseline characteristics. Heterogeneity of effect was assessed according to clusters and baseline edema and related to the additional impact of baseline cardiovascular Sequential Organ Failure Assessment (SOFA) score. We excluded patients with missing values for baseline weight and/or treatment duration.

RESULTS

We identified 2 clusters. The largest (cluster 1; n = 941) included more severely ill patients, with more sepsis, more edema, and more vasopressor therapy (all p < 0.001). Compared to the middle tertile, the probability of harm was greater with the high tertile of NUF rate in patients in cluster 1 and in patients with baseline edema (probability of harm, cluster 1: 99.9%; edema: 99.1%). Moreover, higher baseline cardiovascular SOFA score also increased mortality risk with both high and low compared to middle NUF rates in cluster 1 patients and in patients with edema.

CONCLUSIONS

In CRRT patients, both high and low NUF rates may be harmful, especially in those with edema, sepsis, and greater illness severity. Cardiovascular SOFA scores modulate this association. Additional studies are needed to test these hypotheses, and targeted trials of NUF rates based on risk stratification appear justified.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00221013.

Temporal changes in dialysate [Na+] prescription from 1996 to 2018 and their clinical significance as judged from a meta-regression of clinical trials

Over the last two decades, the clinical care of dialysis patients has refocused sharply on fluid volume control. Dialysate [Na⁺] is a key, albeit under-investigated, clinical tool for manipulation of fluid volume on dialysis. In the article, we firstly use data from the Dialysis Outcomes and Practice Patterns Study to document the global decrease in dialysate [Na⁺] that has occurred from 1996 to 2018, and demonstrate the virtual disappearance of [Na⁺] profiling from routine dialysis practice over the same period. Second, we used data from previously synthesized randomized clinical trial evidence combined with that of a more recently published trail to assess the clinical significance of these changes, estimating the effects of different levels of low dialysate [Na⁺] on key clinical outcomes. Our analyses suggest that current levels of dialysate [Na⁺] in some health jurisdictions are possibly causing harm to many patients, especially given that real world populations are significantly less robust and more vulnerable than clinical trial ones. To quote a recent editorial, "more evidence needed before lower dialysate sodium concentrations can be recommended." That evidence is coming, and no further changes should be made to default customary practice until it is available.

Use of QT Prolonging Medications by Hemodialysis Patients and Individuals Without End-Stage Kidney Disease

Background The rate of sudden cardiac death in the hemodialysis population exceeds that of the general population by >20-fold. Hemodialysis patients may be particularly susceptible to sudden cardiac death provoked by drug-induced QT prolongation because of their substantial cardiovascular disease burden, exposure to electrolyte shifts during dialysis, and extensive polypharmacy. However, population-specific data regarding the frequency and patterns of QT prolonging medication use are limited. Methods and Results We conducted a descriptive drug utilization study using 3 administrative databases, the United States Renal Data System, MarketScan, and Medicare claims. We characterized the extent and patterns of QT prolonging medication use by adult hemodialysis patients and individuals without end-stage kidney disease annually from 2012 to 2016. We also identified instances of high-risk QT prolonging medication use among hemodialysis patients. In total, 338 515 hemodialysis patients and 40.7 million individuals without end-stage kidney disease were studied. Annual utilization rates of QT prolonging medications with known torsades de pointes risk in hemodialysis patients were ~1.4 to ~2.5 times higher than utilization rates in individuals without end-stage kidney disease. Hemodialysis patients with demographic and clinical risk factors for drug-induced QT prolongation were exposed to medications with known torsades de pointes risk more often than patients without risk factors. Conclusions Hemodialysis patients use QT prolonging medications with known torsades de pointes risk more extensively than individuals without end-stage kidney disease. Given the widespread use and instances of high-risk prescribing, future studies evaluating the cardiac safety of these drugs in the hemodialysis population are needed.

Effect of Low-Sodium versus Conventional Sodium Dialysate on Left Ventricular Mass in Home and Self-Care Satellite Facility Hemodialysis Patients: A Randomized Clinical Trial

BACKGROUND

Fluid overload in patients undergoing hemodialysis contributes to cardiovascular morbidity and mortality. There is a global trend to lower dialysate sodium with the goal of reducing fluid overload.

METHODS

To investigate whether lower dialysate sodium during hemodialysis reduces left ventricular mass, we conducted a randomized trial in which patients received either low-sodium dialysate (135 mM) or conventional dialysate (140 mM) for 12 months. We included participants who were aged >18 years old, had a predialysis serum sodium ≥135 mM, and were receiving hemodialysis at home or a self-care satellite facility. Exclusion criteria included hemodialysis frequency >3.5 times per week and use of sodium profiling or hemodiafiltration. The main outcome was left ventricular mass index by cardiac magnetic resonance imaging.

RESULTS

The 99 participants had a median age of 51 years old; 67 were men, 31 had diabetes mellitus, and 59 had left ventricular hypertrophy. Over 12 months of follow-up, relative to control, a dialysate sodium concentration of 135 mmol/L did not change the left ventricular mass index, despite significant reductions at 6 and 12 months in interdialytic weight gain, in extracellular fluid volume, and in plasma B-type natriuretic peptide concentration (ratio of intervention to control). The intervention increased intradialytic hypotension (odds ratio [OR], 7.5; 95% confidence interval [95% CI], 1.1 to 49.8 at 6 months and OR, 3.6; 95% CI, 0.5 to 28.8 at 12 months). Five participants in the intervention arm could not complete the trial because of hypotension. We found no effect on health-related quality of life measures, perceived thirst or xerostomia, or dietary sodium intake.

CONCLUSIONS

Dialysate sodium of 135 mmol/L did not reduce left ventricular mass relative to control, despite improving fluid status.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

The Australian New Zealand Clinical Trials Registry, ACTRN12611000975998.

Cardiac risk assessment for end-stage renal disease patients on the renal transplant waiting list

Cardiovascular disease is a leading cause of morbidity and mortality and is becoming more prevalent as the population ages and risk factors increase. This is most apparent in the end-stage renal disease (ESRD) patient population. In part, this is due to cofactors such as diabetes and hypertension commonly predisposing to progressive renal disease, as well as being a direct consequence of having renal failure. Of all major organ failures, kidney failure is the most likely to be managed chronically using renal replacement therapy and, ultimately, transplant. However, lack of transplant organs and a large renal failure cohort means waiting lists are often quite long and may extend to 5-10 years. Due to the cardiac risk factors inherent in patients awaiting transplant, many succumb to cardiac issues while waiting and present an increased per-procedural cardiac risk that extends into the post-transplant period. We aim to review the epidemiology of coronary artery disease in this population and the etiology as it relates to ESRD and its associated co-factors. We also will review the current approaches, recommendations and evidence for management of these patients as it relates to transplant waiting lists before and after the surgery. Recommendations on how to best manage patients in this cohort revolve around the available evidence and are best customized to the institution and the structure of the program. It is not clear whether the revascularization of patients without symptoms and with a good functional status yields any improvement in outcomes. Therefore, each individual case should be considered based on the risk factors, symptoms and functional status, and approached as part of a multi-disciplinary assessment program.

Association of Net Ultrafiltration Rate With Mortality Among Critically Ill Adults With Acute Kidney Injury Receiving Continuous Venovenous Hemodiafiltration: A Secondary Analysis of the Randomized Evaluation of Normal vs Augmented Level (RENAL) of Renal Replacement Therapy Trial

IMPORTANCE

Net ultrafiltration (NUF) is frequently used to treat fluid overload among critically ill patients, but whether the rate of NUF affects outcomes is unclear.

OBJECTIVE

To examine the association of NUF with survival among critically ill patients with acute kidney injury being treated with continuous venovenous hemodiafiltration.

DESIGN, SETTING, AND PARTICIPANTS

The Randomized Evaluation of Normal vs Augmented Level (RENAL) of Renal Replacement Therapy trial was conducted between December 30, 2005, and November 28, 2008, at 35 intensive care units in Australia and New Zealand among critically ill adults with acute kidney injury who were being treated with continuous venovenous hemodiafiltration. This secondary analysis began in May 2018 and concluded in January 2019.

EXPOSURES

Net ultrafiltration rate, defined as the volume of fluid removed per hour adjusted for patient body weight.

MAIN OUTCOMES AND MEASURES

Risk-adjusted 90-day survival.

RESULTS

Of 1434 patients, the median (interquartile range) age was 67.3 (56.9-76.3) years; 924 participants (64.4%) were male; median (interquartile range) Acute Physiology and Chronic Health Evaluation III score was 100 (84-118); and 634 patients (44.2%) died. Using tertiles, 3 groups were defined: high, NUF rate greater than 1.75 mL/kg/h; middle, NUF rate from 1.01 to 1.75 mL/kg/h; and low, NUF rate less than 1.01 mL/kg/h. The high-tertile group compared with the low-tertile group was not associated with death from day 0 to 6. However, death occurred in 51 patients (14.7%) in the high-tertile group vs 30 patients (8.6%) in the low-tertile group from day 7 to 12 (adjusted hazard ratio [aHR], 1.51; 95% CI, 1.13-2.02); 45 patients (15.3%) in the high-tertile group vs 25 patients (7.9%) in the low-tertile group from day 13 to 26 (aHR, 1.52; 95% CI, 1.11-2.07); and 48 patients (19.2%) in the high-tertile group vs 29 patients (9.9%) in the low-tertile group from day 27 to 90 (aHR, 1.66; 95% CI, 1.16-2.39). Every 0.5-mL/kg/h increase in NUF rate was associated with increased mortality (3-6 days: aHR, 1.05; 95% CI, 1.00-1.11; 7-12 days: aHR, 1.08; 95% CI, 1.02-1.15; 13-26 days: aHR, 1.11; 95% CI, 1.04-1.18; 27-90 days: aHR, 1.13; 95% CI, 1.05-1.22). Using longitudinal analyses, increase in NUF rate was associated with lower survival (β = .056; P < .001). Hypophosphatemia was more frequent among patients in the high-tertile group compared with patients in the middle-tertile group and patients in the low-tertile group (high: 308 of 477 patients at risk [64.6%]; middle: 293 of 472 patients at risk [62.1%]; low: 247 of 466 patients at risk [53.0%]; P < .001). Cardiac arrhythmias requiring treatment occurred among all groups: high, 176 patients (36.8%); middle: 175 patients (36.5%); and low: 147 patients (30.8%) (P = .08).

CONCLUSIONS AND RELEVANCE

Among critically ill patients, NUF rates greater than 1.75 mL/kg/h compared with NUF rates less than 1.01 mL/kg/h were associated with lower survival. Residual confounding may be present from unmeasured risk factors, and randomized clinical trials are required to confirm these findings.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00221013.

Higher ultrafiltration rate is associated with right ventricular mechanical dispersion

Objective:

Ultrafiltration rate is one of the major determinants of adverse outcomes in patients undergoing hemodialysis (HD) therapy. Previous studies have focused on the impact of HD on right ventricular (RV) peak strain values. However, the influence of HD on the temporal characteristics of deformation has not been reported yet. The aim of the present study was to evaluate the impact of high ultrafiltration rate (HUR) on RV mechanical dyssynchrony.

Methods:

Echocardiographic images focused on the RV and left ventricle (LV) were obtained from 60 patients (49.2±17.3 years, 22 female) before and after HD. Patients were divided into two groups according to ultrafiltration rate. Changes in echocardiographic parameters with HD were examined. Two-dimensional speckle-tracking strain analysis was used to assess deformation. Mechanical dispersion was measured as the standard deviation of time to peak longitudinal strain of six segments for RV and 18 segments for LV.

Results:

The average ultrafiltrated volume and ultrafiltration rate were 3000.1±1007.9 mL and 11.4±2.9 mL/kg/h, respectively. Global longitudinal strain (GLS) of the RV and LV decreased after HD in both groups. A significant difference was observed in RV mechanical dispersion with HD for patients in the high ultrafiltration group. A mild statistically insignificant increase in LV mechanical dispersion was also observed after HD.

Conclusion:

HUR has a substantial impact on LV and RV GLS and RV dyssynchrony. Ultrafiltration rates and volumes should be kept as low as possible to achieve hemodynamic stability and tolerability.

Kidney transplantation is associated with reduced myocardial fibrosis. A cardiovascular magnetic resonance study with native T1 mapping

BACKGROUND

The measurement of native T1 through cardiovascular magnetic resonance (CMR) is a noninvasive method of assessing myocardial fibrosis without gadolinium contrast. No studies so far have evaluated native T1 after renal transplantation. The primary aim of the current study is to assess changes in the myocardium native T1 6 months after renal transplantation.

METHODS

We prospectively evaluated 44 renal transplant patients with 3 T CMR exams: baseline at the beginning of transplantation and at 6 months after transplantation.

RESULTS

The native T1 time was measured in the midventricular septum and decreased significantly from 1331 ± 52 ms at the baseline to 1298 ± 42 ms 6 months after transplantation (p = 0.001). The patients were split into two groups through a two-step cluster algorithm: In cluster-1 (n = 30) the left ventricular (LV) mass index and the prevalence of diabetes were lower. In cluster-2 (n = 14) the LV mass index and diabetes prevalence were higher. Decrease in native T1 values was significant only in the patients in cluster-1 (p = 0.001).

CONCLUSIONS

The native myocardial T1 time decreased significantly 6 months after renal transplant, which may be associated with the regression of the reactive fibrosis. The patients with greater baseline LV mass index and the diabetic group did not reach a significant decrease in T1.

Changes of Left and Right Ventricle Mechanics and Function in Patients with End-Stage Renal Disease Undergoing Haemodialysis

Background and objectives: Chronic kidney disease (CKD) increases the risk of cardiovascular diseases even in its early stages and is associated with structural and functional cardiac abnormalities. The aim of this study was to use speckle-tracking echocardiography (STE) to evaluate left and right ventricle mechanics and function, markers of subclinical dysfunction in patients with end-stage renal disease (ESRD) undergoing haemodialysis. Methods: Patients with ESRD undergoing regular haemodialysis and with preserved left ventricle (LV) ejection fraction (EF) (n = 38) were enrolled in this retrospective study. The control group consisted of 32 age-matched persons with normal kidney function (glomerular filtration rate (GFR) >90 mL/min/1.73 m² according to Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)). Conventional 2D echocardiography and STE were performed in all patients. Results: 70 individuals, 31 (44.29%) males and 39 (55.71%) females, were included in the study. There were no significant differences in age, sex and body surface area between the groups. LV end diastolic diameter did not differ between the groups, while LV myocardial mass index was higher in the group of patients on haemodialysis (111.64 ± 27.99 versus 84.21 ± 16.99, p < 0.001) and LV diastolic dysfunction (LVDD) was found in 31 (81.6%) patients of this group. LV global longitudinal strain (GLS) (-22.43 ± 2.71 versus -24.73 ± 2.03, p < 0.001) and LV global circumferential strain (GCS) at the mitral valve and papillary muscles levels (-18.73 ± 3.49 versus -21.67 ± 2.22, p < 0.001; -18.64 ± 2.75 versus -20.42 ± 2.38, p = 0.005, respectively) were significantly lower in haemodialysis group patients. The parameters of the right ventricle (RV) free wall longitudinal function including RV GLS (-22.63 ± 3.04 versus -25.45 ± 2.48, p < 0.001), were reduced in haemodialysis patients compared with the controls. However, RV fractional area change (FAC) did not differ between the groups (p = 0.19). Conclusion: Patients with ESRD and preserved LV ejection fraction undergoing haemodialysis had a higher prevalence of LVDD and impaired LV longitudinal and circumferential deformation indices, as well as reduced RV longitudinal function and deformation parameters compared with the age-matched healthy controls. STE helps to detect subclinical LV and RV dysfunction in chronic haemodialysis patients.

Obstructive Sleep Apnea Increases Sudden Cardiac Death in Incident Hemodialysis Patients

BACKGROUND

Mortality in end-stage renal disease (ESRD) occurs predominantly from cardiovascular disease (CVD) and sudden cardiac death (SCD). Obstructive sleep apnea (OSA) is characterized by periodic airflow limitation associated with sleep arousal and oxygen desaturation and is prevalent in patients with ESRD. Whether OSA increases the risk for SCD, cardiovascular and all-cause mortality among hemodialysis patients remains unknown.

METHODS

In a prospective cohort of 558 incident hemodialysis patients, we examined the association of OSA with all-cause mortality, cardiovascular mortality, and SCD using Cox proportional hazards models controlling for traditional CVD risk factors.

RESULTS

Sixty-six incident hemodialysis patients (12%) had OSA. Mean age (56 years) and percentage of males (56%) were identical in OSA and no-OSA groups. Fewer African Americans had OSA than non-African Americans (9 vs. 18%, respectively). Participants with OSA had higher body-mass index, Charlson comorbidity score, and left ventricular mass index and greater prevalence of diabetes and coronary artery disease. During 1,080 person-years of follow-up, 104 deaths occurred, 29% of which were cardiovascular. OSA was associated with a higher risk of all-cause mortality (HR 1.90 [95% CI 1.04-3.46]) and cardiovascular mortality (HR 3.62 [95% CI 1.36-9.66]) after adjusting for demographics and body-mass index. OSA was associated with a higher risk of SCD after adjusting for demographics (HR 3.28 [95% CI 1.12-9.57]) and multiple cardiovascular risk factors.

CONCLUSIONS

Incident hemodialysis patients with OSA are at increased risk of all-cause and cardiovascular mortality and SCD. Future studies should assess the impact of screening for OSA and OSA-targeted interventions on mortality in ESRD.

Novel cardiac nuclear magnetic resonance method for noninvasive assessment of myocardial fibrosis in hemodialysis patients

Left ventricular hypertrophy and myocardial fibrosis frequently occur in patients with end-stage renal disease receiving hemodialysis therapy and are associated with poor prognosis. Native T1 mapping is a novel cardiac magnetic resonance imaging technique that measures native myocardial T1 relaxation, a surrogate of myocardial fibrosis. Here we compared global and segmental native myocardial T1 time and global longitudinal, circumferential and segmental strain, and cardiac function of 35 hemodialysis patients and 22 control individuals. The median native global T1 time was significantly higher in the hemodialysis than the control group (1270 vs. 1085 ms), with the septal regions of hemodialysis patients having significantly higher median T1 times than nonseptal regions (1293 vs. 1252 ms). The mean peak global circumferential strain and global longitudinal strain were both significantly reduced in hemodialysis patients compared with controls (-18.3 vs. -21.7 and -16.1 vs. -20.4, respectively). Systolic strain was also significantly reduced in the septum compared with the nonseptal myocardium in hemodialysis patients (-16.2 vs. -21.9) but not in control subjects. Global circumferential strain and longitudinal strain significantly correlated with global native T1 values (r = 0.41 and 0.55, respectively), and the septal native T1 significantly correlated with the septal systolic strain (r = 0.46). Thus, myocardial fibrosis may be assessed noninvasively with native T1 mapping; the interventricular septum appears to be particularly prone to the development of fibrosis in hemodialysis patients.

Dialysate Sodium: Rationale for Evolution over Time

Oligo-anuric individuals receiving hemodialysis (HD) are dependent on the dialysis machine to regulate sodium and water balance. Interest in adjusting the dialysate sodium concentration to promote tolerance of the HD procedure dates back to the early years of dialysis therapy. Evolution of dialysis equipment technologies and clinical characteristics of the dialysis population have prompted clinicians to increase the dialysate sodium concentration over time. Higher dialysate sodium concentrations generally promote hemodynamic stabilization and reduce intradialytic symptoms but often do so at the expense of stimulating thirst and promoting volume expansion. The opposite may be true for lower dialysate sodium concentrations. Observational data suggest that the association between dialysate sodium and outcomes may differ by serum sodium levels, supporting the trend toward individualization of the dialysate sodium prescription. However, lack of randomized controlled clinical trial data, along with operational safety concerns related to individualized dialysate sodium prescriptions, have prevented expert consensus regarding the optimal approach to the dialysate sodium prescription.

Renal dysfunction and diastolic impairment among British ethnic minorities with hypertension: the Ethnic-Echocardiographic Heart of England Screening Study

Renal dysfunction is frequently associated with left ventricular (LV) hypertrophy and diastolic dysfunction in hypertensive patients. Limited data exist on renal dysfunction and diastolic impairment among British ethnic minorities with hypertension. We studied associations between renal impairment and diastolic dysfunction in hypertensive subjects of African-Caribbean and South Asian origin. Five hundred and ten hypertensive subjects with ejection fraction ⩾55% and with no history of ischaemic heart disease/valve pathology were included from the original population of the Ethnic-Echocardiographic Heart of England Screening Study (E-ECHOES). Diastolic function and cardiac remodelling were measured by echocardiography. LV hypertrophy was common and present in 62% of patients with normal estimated glomerular filtration rate (eGFR, >90 ml min^-1 per 1.73 m²), 73% in those with eGFR 60-89 ml min^-1 per 1.73 m² and 87% with eGFR <60 ml min^-1 per 1.73 m². On both univariate and multivariable linear regression, reduced eGFR was associated with higher LV mass index (LVMI, P=0.01 and P=0.039, respectively). On multivariable analyses, increased LVMI (but not eGFR) was an independent predictor of echocardiographic parameters of diastolic dysfunction. Higher LVMI was an independent predictor of all-cause or cardiovascular death on multivariable analyses (both P=0.002), but not eGFR. LV hypertrophy is common in minority ethnic groups with hypertension, especially in the presence of renal dysfunction. Increased LVMI rather than renal impairment per se is a major determinant of diastolic dysfunction and increased risk of cardiovascular or all-cause death among hypertensive patients without end-stage renal failure.

Is Kidney Transplantation a Better State of CKD? Impact on Diagnosis and Management

Patients with CKD are at increased risk for cardiovascular events, hospitalizations, and mortality. Kidney transplantation (KTx) is the preferred treatment for end-stage kidney disease. Although comorbidities including anemia and bone and mineral disease improve or are even halted after KTx, kidney transplant recipients carry higher cardiovascular mortality risk than the general population, as well as an increased risk of infections, malignancies, fractures, and obesity. When comparing CKD with CKD after transplantation (CKD-T), the rate of decline of estimated glomerular filtration rate (eGFR) is significantly lower in CKD-T. Higher rate of decline of eGFR has been associated with increased risk of mortality. However, due to the significant increased risk of mortality due to cardiovascular events, infections, and malignancies, many kidney transplant recipients may not benefit of decline in the rate of eGFR. Patients with CKD-T are a unique subset of patients with multiple traditional and transplant-specific risk factors. Proper management and appropriate preventive health measures may improve long-term patient and allograft survival in patients with CKD-T.

Rapid ultrafiltration rates and outcomes among hemodialysis patients: re-examining the evidence base

PURPOSE OF REVIEW

This review critically summarizes the evidence linking ultrafiltration rates to adverse outcomes among hemodialysis patients and provides research recommendations to address knowledge gaps.

RECENT FINDINGS

Growing evidence suggests that fluid-related factors play important roles in hemodialysis patient outcomes. Ultrafiltration rate - the rate of fluid removal during hemodialysis - is one such factor. Existing observational data suggest a robust association between greater ultrafiltration rates and adverse cardiovascular outcomes, and such findings are supported by plausible physiologic rationale. Potential mechanistic pathways include ultrafiltration-related ischemia to the heart, brain, and gut, and volume overload-precipitated cardiac stress from reactive measures to ultrafiltration-induced hemodynamic instability. Inter-relationships among ultrafiltration rates and other fluid measures, such as interdialytic weight gain and chronic volume expansion, render the specific role of ultrafiltration rates in adverse outcomes difficult to study. Randomized trials must be conducted to confirm epidemiologic findings and examine the effect of ultrafiltration rate reduction on clinical and patient-centered outcomes.

SUMMARY

Compelling observational data demonstrate an association between more rapid ultrafiltration rates and adverse clinical outcomes. Before translating these findings into clinical practice, randomized trials are needed to verify observational data results and to identify effective strategies to mitigate ultrafiltration-related risk.

Sudden cardiac death in non-dialysis chronic kidney disease patients

BACKGROUND

A relatively high proportion of deaths in dialysis patients occur suddenly and unexpectedly. The incidence of sudden cardiac death (SCD) in non-dialysis advanced chronic kidney disease (CKD) stages has been less well investigated.

OBJECTIVE

This study aims to determine the incidence and predictors of SCD in a cohort of 1078 patients with CKD not yet on dialysis.

METHODS

Prospective observational cohort study, which included patients with advanced CKD not yet on dialysis (stage 4-5). The association between baseline variables and SCD was assessed using Cox and competing-risk (Fine and Grey) regression models. Demographic, clinical information, medication use, and baseline biochemical parameters of potential interest were included as covariates.

RESULTS

During the study period (median follow-up time 12 months), 210 patients died (19%), and SCD occurred in 34 cases (16% of total deaths). All-cause mortality and SCD incidence rates were 113 (95% CI: 99-128), and 18 (95% CI: 13-26) events per 1000 patients/year, respectively. By Cox regression analysis, covariates significantly associated with SCD were: Age, comorbidity index, and treatment with antiplatelet drugs. This latter covariate showed a beneficial effect over the development of SCD. By competing-risk regression, in which the competing event was non-sudden death from any cause, only age and comorbidity index remained significantly associated with SCD.

CONCLUSIONS

SCD is relatively common in non-dialysis advanced CKD patients. SCD was closely related to age and comorbidity, and some indirect data from this study suggest that unrecognised or undertreated cardiovascular disease may predispose to a higher risk of SCD.

Electrophysiologic Substrate and Risk of Mortality in Incident Hemodialysis

The single leading cause of mortality on hemodialysis is sudden cardiac death. Whether measures of electrophysiologic substrate independently associate with mortality is unknown. We examined measures of electrophysiologic substrate in a prospective cohort of 571 patients on incident hemodialysis enrolled in the Predictors of Arrhythmic and Cardiovascular Risk in End Stage Renal Disease Study. A total of 358 participants completed both baseline 5-minute and 12-lead electrocardiogram recordings on a nondialysis day. Measures of electrophysiologic substrate included ventricular late potentials by the signal-averaged electrocardiogram and spatial mean QRS-T angle measured on the averaged beat recorded within a median of 106 days (interquartile range, 78-151 days) from dialysis initiation. The cohort was 59% men, and 73% were black, with a mean±SD age of 55±13 years. Transthoracic echocardiography revealed a mean±SD ejection fraction of 65.5%±12.0% and a mean±SD left ventricular mass index of 66.6±22.3 g/m^2.7 During 864.6 person-years of follow-up, 77 patients died; 35 died from cardiovascular causes, of which 15 were sudden cardiac deaths. By Cox regression analysis, QRS-T angle ≥75° significantly associated with increased risk of cardiovascular mortality (hazard ratio, 2.99; 95% confidence interval, 1.31 to 6.82) and sudden cardiac death (hazard ratio, 4.52; 95% confidence interval, 1.17 to 17.40) after multivariable adjustment for demographic, cardiovascular, and dialysis factors. Abnormal signal-averaged electrocardiogram measures did not associate with mortality. In conclusion, spatial QRS-T angle but not abnormal signal-averaged electrocardiogram significantly associates with cardiovascular mortality and sudden cardiac death independent of traditional risk factors in patients starting hemodialysis.

Cardiac Biomarkers and Left Ventricular Hypertrophy in Asymptomatic Hemodialysis Patients

BACKGROUND:

Cardiac biomarkers are often elevated in dialysis patients showing the presence of left ventricular dysfunction. The aim of the study is to establish the plasma levels of high-sensitivity cardiac troponin T (hs TnT), precursor of B-natriuretic peptide (NT-proBNP) and high sensitivity C-reactive protein (hs CRP) and their relation to the presence of left ventricular hypertrophy (LVH) in patients undergoing hemodialysis without signs of acute coronary syndrome or heart failure.

MATERIAL AND METHODS:

We studied 48 patients - 26 men and 22 women. Pre and postdialysis levels of hs cTnT, NT-proBNP and hs CRP were measured at week interim procedure. Patients were divided in two groups according to the presence of echocardiographic evidence of LVH - gr A - 40 patients (with LVH), and gr B - 8 patients (without LVH).

RESULTS:

In the whole group of patients was found elevated predialysis levels of all three biomarkers with significant increase (p < 0.05) after dialysis with low-flux dialyzers. Predialysis values of NT-proBNP show moderate positive correlation with hs cTnT (r = 0.47) and weaker with hs CRP (r = 0.163). Such dependence is observed in postdialysis values of these biomarkers. There is a strong positive correlation between the pre and postdialysis levels: for hs cTnT (r = 0.966), for NT-proBNP (r = 0.918) and for hs CRP (r = 0.859). It was found a significant difference in the mean values of hs cTnT in gr. A and gr. B (0.07 ± 0.01 versus 0.03 ± 0.01 ng/mL, p < 0.05) and NT-proBNP (15,605.8 ± 2,072.5 versus 2,745.5 ± 533.55 pg/mL, p < 0.05). Not find a significant difference in hs CRP in both groups.

CONCLUSIONS:

The results indicate the relationship of the studied cardiac biomarkers with LVH in asymptomatic patients undergoing hemodialysis treatment.

Low Potassium Dialysate as a Protective Factor of Sudden Cardiac Death in Hemodialysis Patients with Hyperkalemia

AIM

Hyperkalemia increases the risk of sudden cardiac death (SCD) in hemodialysis patients. Our objective was to determine the association between administering low potassium dialysate to hyperkalemic hemodialysis patients and SCD.

METHODS

We conducted a retrospective cohort study with patients undergoing maintenance hemodialysis from May 1, 2006, through December 31, 2013. The dialysate composition was adjusted over time according to monthly laboratory results. A 1.0 mEq/L potassium dialysate was applied in patients with predialysis hyperkalemia (>5.5 mEq/L) and was included as a time-dependent confounding factor. The clinical characteristics of enrolled patients, the incidence and timing of SCD and risk factors for all-cause mortality and SCD were analyzed.

RESULTS

There were 312 patients on maintenance hemodialysis during the study period. One hundred and fifty-seven patients had been dialyzed against a 1.0 mEq/L potassium dialysate at least once. The rates of all-cause mortality and SCD were 48.17 and 20.74 per 1000 patient-years, respectively. A 1.12-fold increase in the risk of SCD in the 24-hour period starting with the hemodialysis procedure and a 1.36-fold increase in the 24 hours preceding a weekly cycle were found (p = 0.017). Multivariate Cox proportional hazards models showed that age, diabetes mellitus and predialysis hyperkalemia (>5.0 mEq/L) were significant predictors of all-cause mortality and SCD. Exposure to 1.0 mEq/L potassium dialysate, Kt/V, and serum albumin were independent protective factors against all-cause mortality. Only exposure to 1.0 mEq/L potassium dialysate significantly prevented SCD (hazard ratio = 0.33, 95% CI = 0.13-0.85).

CONCLUSIONS

Using low potassium dialysate in hyperkalemic hemodialysis patients may prevent SCD.

Eccentric Left Ventricular Hypertrophy and Sudden Death in Patients with End-Stage Kidney Disease

BACKGROUND/AIMS

Both all-cause and cardiovascular mortality risks are extremely high in patients with end-stage kidney disease (ESKD). Sudden death accounts for approximately one-quarter of all fatal events. Left ventricular hypertrophy (LVH) is a known risk factor for mortality and can be divided in 2 types: concentric and eccentric. This study evaluated possible differences in all-cause mortality, cardiovascular mortality and sudden death between prevalent ESKD patients with concentric and eccentric LVH.

METHODS

Participants of the CONvective TRAnsport STudy (CONTRAST) who underwent transthoracic echocardiography (TTE) at baseline were analyzed. In patients with LVH, a relative wall thickness of ≤0.42 was considered eccentric and >0.42 was considered concentric hypertrophy. Cox proportional hazards models, adjusted for potential confounders, were used to calculate hazard ratios (HRs) of patients with eccentric LVH versus patients with concentric LVH for all-cause mortality, cardiovascular mortality and sudden death.

RESULTS

TTE was performed in 328 CONTRAST participants. LVH was present in 233 participants (71%), of which 87 (37%) had concentric LVH and 146 (63%) eccentric LVH. The HR for all-cause mortality of eccentric versus concentric LVH was 1.14 (p = 0.52), 1.79 (p = 0.12) for cardiovascular mortality and 4.23 (p = 0.02) for sudden death in crude analyses. Propensity score-corrected HR for sudden death in patients with eccentric LVH versus those with concentric LVH was 5.22 (p = 0.03).

CONCLUSIONS

(1) The hazard for all-cause mortality, cardiovascular mortality and sudden death is markedly increased in patients with LVH. (2) The sudden death risk is significantly higher in ESKD patients with eccentric LVH compared to subjects with concentric LVH.

Left Ventricular Hypertrophy in Chronic Kidney Disease Patients: From Pathophysiology to Treatment

Cardiovascular diseases represent the main causes of morbidity and mortality in patients with chronic kidney disease (CKD). According to a well-established classification, cardiovascular involvement in CKD can be set in the context of cardiorenal syndrome type 4. Left ventricular hypertrophy (LVH) represents a key feature to provide an accurate picture of systolic-diastolic left heart involvement in CKD patients. Cardiovascular involvement is present in about 80% of prevalent hemodialysis patients, and it is evident in CKD patients since stage IIIb-IV renal disease (according to the K/DOQI CKD classification). According to the definition of cardiorenal syndrome type 4, kidney disease is detected before the development of heart failure, although timing of the diagnosis is not always possible. The evaluation of LVH is a bit heterogeneous, and few standard imaging methods can provide the accuracy of either CT- or MRI-derived left ventricular mass. Key principles in the treatment of LVH in CKD patients are mainly based on anemia and blood pressure control, together with the management of secondary hyperparathyroidism and sudden cardiac death prevention. This review is mainly focused on the clinical aspects of CKD-related LVH to provide practical guidelines both for cardiologists and nephrologists in the daily clinical approach to CKD patients.

Screening and risk stratification of coronary artery disease in end-stage renal disease

End-stage renal disease (ESRD) is a growing global health problem with major health and economic implications. Cardiovascular complication is the major cause of morbidity and mortality in this population. Clustering of traditional atherosclerotic risk factors, such as diabetes, systemic inflammation, and altered mineral metabolism, contributes to enhanced systemic atherosclerosis in patients with ESRD. Prevalence of obstructive coronary artery disease (CAD) on coronary angiography exceeds 50% in this population. Despite having extensive CAD and vascular disease, patients with ESRD often do not present with classic symptoms because of impaired exercise capacity and diabetes. Furthermore, clinical trial data are exceedingly lacking in this population, resulting in considerable clinical equipoise regarding the optimal approach to the identification and subsequent management of CAD in these patients. Traditional clinical screening tools, including conventional risk prediction models, are significantly limited in their predictive accuracy for cardiovascular events in patients with ESRD. Noninvasive cardiac stress imaging modalities, such as nuclear perfusion and echocardiography, have been shown to improve the traditional clinical model in identifying the presence of CAD. Furthermore, they add incremental prognostic information to angiographic data. Novel imaging techniques and biomarker assays hold significant promise in further improving the ability to identify and risk-stratify for CAD. This review focuses on the current understanding of the clinical risk profile of asymptomatic patients with ESRD with an emphasis on the strengths and limitations of various noninvasive cardiovascular imaging modalities, including the role of novel methods in refining risk prediction. In addition, issues and challenges pertaining to the optimal timing of initial risk assessment ("screening") and possible repeat screening ("surveillance") are addressed. We also summarize the current data on the approach to the patient with ESRD being evaluated for transplantation in the context of recent guidelines and position statements by various professional societies.

Standardising haemodialysis care by restricting nutrition during dialysis: introducing a quality improvement initiative for renal outpatients

A number of relevant issues are considered which show that it is essential to address the issue of in-centre meals during dialysis. This discussion paper critically explores the potential complications posed to patients who consume a large calorific intake during their dialysis treatment. The mission is to appeal to more dialysis units and outpatient departments to gradually implement a 'no food' policy during regular scheduled dialysis treatment sessions. The authors aim to put forward the significances and challenges and offer some possible solutions when introducing a 'no eating policy' like this into dialysis units. Nutritional supplements could, however, be offered on an as required basis.

Glucose Serum Concentrations and Cardiovascular Disease in Patients on the End Stage of Renal Disease without Diabetes Mellitus

Background/Aim: It is still controversial whether tighter glycemic control is associated with better clinical outcomes in patients with kidney failure. We examined the association between glucose serum concentrations and cardiovascular disease in patients on the end stage of renal disease without diabetes mellitus. Methods: We studied 76 patients on on-line hemodiafiltration. Cardiovascular disease was defined by the existence of coronary disease (CD). Arterial stiffness was measured as carotid-femoral pulse wave velocity (c-fPWV) and carotid augmentation index (AIx). The concentrations of beta2-microglobulin (β2M) and insulin were measured by radioimmunoassays and insulin resistance by HOMA-IR. We built a logistic-regression analysis to examine the role of glucose on cardiovascular disease after adjustment for the traditional and specific risk factors for dialysis patients. Results: Serum glucose was positively correlated with beta2M, insulin and HOMA-IR (r = 0.361, p = 0.002, r = 0.581, p = 0.001 and r = 0.753, p = 0.001 respectively). Logistic-regression analysis did not show significant impact of glucose concentrations on cardiovascular disease after adjustment for traditional and specific risk factors. Conclusions: The association between elevated glucose serum concentrations and represented by coronary syndrome cardiovascular disease in patients on the end stage of renal disease without diabetes mellitus was not found significant.

The relationship between glycemic control, beta2-microglobulin and inflammation in patients on maintenance dialysis treatment

BACKGROUND

Hyperglycemia appears to play a significant role on the inflammatory cytokines production. Beta2-microglobulin (beta2M) is accumulated in the circulation of dialysis patients. We studied the relationship between glycemic control defined by glucose serum concentrations and insulin resistance, beta2M and markers of inflammation in patients on renal replacement therapies with or/and without diabetes mellitus.

METHODS

We enrolled 96 dialyzed patients, 62 males and 34 females. The treatment modalities which were applied were : regular hemodialysis (HD, n = 34), predilution hemodiafiltration (HDF, n = 42) and peritoneal dialysis (PD, n = 20). Dialysis adequacy was defined by Kt/V for urea.Beta2M and insulin serum concentrations were measured by radioimmunoassays. hsCRP and TNF-α serum concentrations were measured by ELISA. Insulin resistance was calculated using the homeostasis model assessment of insulin resistance (HOMA-IR).We examined the association of elevated serum glucose with inflammatory factors and we built a multivariable model to investigate if glucose could be a potential determinant of beta2M serum levels.

RESULTS

Serum glucose was positively correlated with beta2M and TNF-α (r = 0.320, p = 0.002 and r = 0.215, p = 0.03 respectively).We observed significant association between the patients with higher serum glucose concentrations and the patients with greater beta2Μ concentrations (x(2) = 4.44, p = 0.03). Multivariable model showed that glucose acts as a significant independent determinant of beta2M adjusting for age, gender, dialysis modality and metabolic acidosis status.

CONCLUSIONS

The elevated glucose concentrations were positively associated with both, greater beta2M serum concentrations and up-regulated inflammatory procedure in dialysis patients with or/and without diabetes mellitus.

Associations of Posthemodialysis Weights above and below Target Weight with All-Cause and Cardiovascular Mortality

BACKGROUND AND OBJECTIVES

Fluid removal via ultrafiltration is a primary function of hemodialysis, and inadequate volume control is associated with significant morbidity and mortality among chronic dialysis patients. Treatment-to-treatment fluid removal goals are typically calculated on the basis of interdialytic weight gain and prescribed target weight. The clinical effect of frequent missed target weights is unclear. This study was designed to evaluate the associations of postdialysis weights above and below the prescribed target weight (separately) and outcomes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data were taken from a national cohort of 10,785 prevalent, thrice-weekly, in-center hemodialysis patients dialyzing from 2005 to 2008 (median time at risk, 2.1 [25th percentile, 75th percentile] years) at a single dialysis organization. Patients were characterized as having an above target weight miss if their postdialysis weight was >2 kg above target weight in at least 30% of baseline treatments (14.6% of cohort), or they were characterized as control otherwise. Below target weight miss characterization was analogous for patients with postdialysis weight >2 kg below target weight (6.6% of cohort). Coprimary endpoints were all-cause and cardiovascular mortality.

RESULTS

Above target weight miss in at least 30% of treatments (versus not) was associated with greater all-cause mortality (adjusted hazard ratio, 1.28; 95% confidence interval, 1.15 to 1.43); and below target weight miss in at least 30% of treatments (versus not) was associated with greater all-cause mortality (adjusted hazard ratio, 1.22; 95% confidence interval, 1.05 to 1.40). Both above and below target weight misses were also significantly associated with greater cardiovascular mortality. Secondary analyses demonstrated dose-response relationships between target weight misses and mortality. Results from sensitivity analyses considering the difference in postdialysis and target weights as a proportion of body weight were analogous to the primary results.

CONCLUSIONS

Postdialysis weights >2 kg above and below target weight are associated with higher all-cause and cardiovascular mortality. Consistent target weight achievement is a viable target for improving fluid management.

Effect of icodextrin on heart rate variability in diabetic patients on peritoneal dialysis

INTRODUCTION

Spectral analysis of heart rate variability is a noninvasive method for evaluating autonomic cardiovascular dysfunction under various clinical conditions, such as in dialysis patients, in whom an imbalance between the sympathetic and parasympathetic nervous system appears to be an important risk factor for sudden cardiovascular death and arrhythmia. ♢

OBJECTIVE

We compared the effect of icodextrin-based dialysis solution, an option that allows for better metabolic and fluid overload control, with that of glucose-based dialysis fluid on sympathetic and parasympathetic activity in the heart, as assessed by heart rate variability, in diabetic patients on peritoneal dialysis (PD). ♢

METHODS

This secondary analysis uses data from a randomized controlled trial in diabetic PD patients with high or high-average peritoneal transport using icodextrin-based (ICO group, n = 30) or glucose-based (GLU group, n = 29) solutions for the long dwell. All patients underwent 24-hour electrocardiographic Holter monitoring at baseline, and at 6 and 12 months of follow-up. ♢

RESULTS

We observed no significant differences between the groups in most of the variables analyzed, although values were, in general, below reference values. In the ICO group, total power and both low- and high-frequency power in normalized units increased, but the percentage of RR intervals with variation of more than 50 ms declined over time; in the GLU group, all those values declined. Plasma catecholamine levels were higher at baseline and declined over time. ♢

CONCLUSIONS

These results indicate a partial recovery of sympathetic activity in the ICO group, probably because of better extracellular fluid control and lower exposure to glucose with the use of icodextrin-based dialysis solutions.

The interplay between CKD, sudden cardiac death, and ventricular arrhythmias

CKD patients face an increased risk of cardiovascular disease mortality, and the risk of sudden cardiac death (SCD) increases as kidney function declines. Risk factors for SCD are poorly understood and understudied among CKD patients. In the general population, coronary heart disease-associated risk factors are the most important determinants of SCD risk, but among CKD patients, there is evidence that these factors play a much smaller role. Complex relationships between CKD-specific risk factors, structural heart disease, and arrhythmic triggers contribute to the high risk of SCD and ventricular arrhythmias and modulate the effectiveness of available therapies. This review examines recent data on the epidemiology, pathophysiology, and mechanisms of SCD among CKD patients and examines current evidence regarding the use of pharmacologic and device-based therapies for management of SCD risk.

Treatment of established left ventricular hypertrophy with fibroblast growth factor receptor blockade in an animal model of CKD

BACKGROUND

Activation of fibroblast growth factor receptor (FGFR)-dependent signalling by FGF23 may contribute to the complex pathogenesis of left ventricular hypertrophy (LVH) in chronic kidney disease (CKD). Pan FGFR blockade by PD173074 prevented development of LVH in the 5/6 nephrectomy rat model of CKD, but its ability to treat and reverse established LVH is unknown.

METHODS

CKD was induced in rats by 5/6 nephrectomy. Two weeks later, rats began treatment with vehicle (0.9% NaCl) or PD173074, 1 mg/kg once-daily for 3 weeks. Renal function was determined by urine and blood analyses. Left ventricular (LV) structure and function were determined by echocardiography, histopathology, staining for myocardial fibrosis (Sirius-Red) and investigating cardiac gene expression profiles by real-time PCR.

RESULTS

Two weeks after inducing CKD by 5/6 nephrectomy, rats manifested higher (mean ± SEM) systolic blood pressure (208 ± 4 versus 139 ± 3 mmHg; P < 0.01), serum FGF23 levels (1023 ± 225 versus 199 ± 9 pg/mL; P < 0.01) and LV mass (292 ± 9 versus 220 ± 3 mg; P < 0.01) when compared with sham-operated animals. Thereafter, 3 weeks of treatment with PD173074 compared with vehicle did not significantly change blood pressure, kidney function or metabolic parameters, but significantly reduced LV mass (230 ± 14 versus 341 ± 33 mg; P < 0.01), myocardial fibrosis (2.5 ± 0.7 versus 5.4 ± 0.95% staining/field; P < 0.01) and cardiac expression of genes associated with pathological LVH, while significantly increasing ejection fraction (18 versus 2.5% post-treatment increase; P < 0.05).

CONCLUSIONS

FGFR blockade improved cardiac structure and function in 5/6 nephrectomy rats with previously established LVH. These data support FGFR activation as a potentially modifiable, blood pressure-independent molecular mechanism of LVH in CKD.

Heart failure in patients with chronic kidney disease: a systematic integrative review

Introduction. Heart failure (HF) is highly prevalent in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD) and is strongly associated with mortality in these patients. However, the treatment of HF in this population is largely unclear. Study Design. We conducted a systematic integrative review of the literature to assess the current evidence of HF treatment in CKD patients, searching electronic databases in April 2014. Synthesis used narrative methods. Setting and Population. We focused on adults with a primary diagnosis of CKD and HF. Selection Criteria for Studies. We included studies of any design, quantitative or qualitative. Interventions. HF treatment was defined as any formal means taken to improve the symptoms of HF and/or the heart structure and function abnormalities. Outcomes. Measures of all kinds were considered of interest. Results. Of 1,439 results returned by database searches, 79 articles met inclusion criteria. A further 23 relevant articles were identified by hand searching. Conclusions. Control of fluid overload, the use of beta-blockers and angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, and optimization of dialysis appear to be the most important methods to treat HF in CKD and ESRD patients. Aldosterone antagonists and digitalis glycosides may additionally be considered; however, their use is associated with significant risks. The role of anemia correction, control of CKD-mineral and bone disorder, and cardiac resynchronization therapy are also discussed.

Sailing between Scylla and Charybdis: the high serum K-low dialysate K quandary

In HD patients, the optimal choice of dialysate K concentration is of paramount importance. Recent large observational studies have documented an association between low dialysate K concentration (< 2 or even <3 mEq/L) and a higher risk of sudden death. In this review, we first briefly discuss the available data concerning the link between hypokalemia and negative outcomes in non-CKD populations, especially after an acute myocardial infarction or in congestive heart failure. We next review the pathophysiology of the arrhythmogenic effect related to K fluxes during HD and discuss the dialytic strategies aiming at making potassium fall more gradual and thus at reducing the electrical disturbances triggered by the HD session. We conclude with practical recommendations regarding the optimal choice of K bath and the importance of more frequent monitoring of serum K in some clinical scenarios.

Left ventricular mass in dialysis patients, determinants and relation with outcome. Results from the COnvective TRansport STudy (CONTRAST)

BACKGROUND AND OBJECTIVES

Left ventricular mass (LVM) is known to be related to overall and cardiovascular mortality in end stage kidney disease (ESKD) patients. The aims of the present study are 1) to determine whether LVM is associated with mortality and various cardiovascular events and 2) to identify determinants of LVM including biomarkers of inflammation and fibrosis.

DESIGN SETTING PARTICIPANTS & MEASUREMENTS

Analysis was performed with data of 327 ESKD patients, a subset from the CONvective TRAnsport STudy (CONTRAST). Echocardiography was performed at baseline. Cox regression analysis was used to assess the relation of LVM tertiles with clinical events. Multivariable linear regression models were used to identify factors associated with LVM.

RESULTS

Median age was 65 (IQR: 54-73) years, 203 (61%) were male and median LVM was 227 (IQR: 183-279) grams. The risk of all-cause mortality (hazard ratio (HR) = 1.73, 95% CI: 1.11-2.99), cardiovascular death (HR = 3.66, 95% CI: 1.35-10.05) and sudden death (HR = 13.06; 95% CI: 6.60-107) was increased in the highest tertile (>260 grams) of LVM. In the multivariable analysis positive relations with LVM were found for male gender (B = 38.8±10.3), residual renal function (B = 17.9±8.0), phosphate binder therapy (B = 16.9±8.5), and an inverse relation for a previous kidney transplantation (B = -41.1±7.6) and albumin (B = -2.9±1.1). Interleukin-6 (Il-6), high-sensitivity C-reactive protein (hsCRP), hepcidin-25 and connective tissue growth factor (CTGF) were not related to LVM.

CONCLUSION

We confirm the relation between a high LVM and outcome and expand the evidence for increased risk of sudden death. No relationship was found between LVM and markers of inflammation and fibrosis.

TRIAL REGISTRATION

Controlled-Trials.com ISRCTN38365125.

Fish oil for prevention of sudden death in hemodialysis patients?

Friedman et al. report that hemodialysis patients with the highest levels of n-3 fatty acids had impressively low odds of sudden cardiac death. The study is limited by a small sample size, and the analysis relies on only a single baseline measurement of blood levels. Recent randomized evidence indeed fails to support that n-3 fatty acids may prevent sudden death in nonrenal patients. More evidence is needed to advocate fish oil in this setting.

Rationale and design of the Sodium Lowering In Dialysate (SoLID) trial: a randomised controlled trial of low versus standard dialysate sodium concentration during hemodialysis for regression of left ventricular mass

BACKGROUND

The current literature recognises that left ventricular hypertrophy makes a key contribution to the high rate of premature cardiovascular mortality in dialysis patients. Determining how we might intervene to ameliorate left ventricular hypertrophy in dialysis populations has become a research priority. Reducing sodium exposure through lower dialysate sodium may be a promising intervention in this regard. However there is clinical equipoise around this intervention because the benefit has not yet been demonstrated in a robust prospective clinical trial, and several observational studies have suggested sodium lowering interventions may be deleterious in some dialysis patients.

METHODS/DESIGN

The Sodium Lowering in Dialysate (SoLID) study is funded by the Health Research Council of New Zealand. It is a multi-centre, prospective, randomised, single-blind (outcomes assessor), controlled parallel assignment 3-year clinical trial. The SoLID study is designed to study what impact low dialysate sodium has upon cardiovascular risk in dialysis patients. The study intends to enrol 118 home hemodialysis patients from 6 sites in New Zealand over 24 months and follow up each participant over 12 months. Key exclusion criteria are: patients who dialyse more frequently than 3.5 times per week, pre-dialysis serum sodium of <135 mM, and maintenance hemodiafiltration. In addition, some medical conditions, treatments or participation in other dialysis trials, which contraindicate the SoLID study intervention or confound its effects, will be exclusion criteria. The intervention and control groups will be dialysed using dialysate sodium 135 mM and 140 mM respectively, for 12 months. The primary outcome measure is left ventricular mass index, as measured by cardiac magnetic resonance imaging, after 12 months of intervention. Eleven or more secondary outcomes will be studied in an attempt to better understand the physiologic and clinical mechanisms by which lower dialysate sodium alters the primary end point.

DISCUSSION

The SoLID study is designed to clarify the effect of low dialysate sodium upon the cardiovascular outcomes of dialysis patients. The study results will provide much needed information about the efficacy of a cost effective, economically sustainable solution to a condition which is curtailing the lives of so many dialysis patients.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry number: ACTRN12611000975998.

Disentangling the ultrafiltration rate-mortality association: the respective roles of session length and weight gain

BACKGROUND AND OBJECTIVES

Rapid ultrafiltration rate is associated with increased mortality among hemodialysis patients. Ultrafiltration rates are determined by interdialytic weight gain and session length. Although both interdialytic weight gain and session length have been linked to mortality, the relationship of each to mortality, independent of the other, is not adequately defined. This study was designed to evaluate whether shorter session length independent of weight gain and larger weight gain independent of session length are associated with increased mortality.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Data were taken from a national cohort of 14,643 prevalent, thrice-weekly, in-center hemodialysis patients dialyzing from 2005 to 2009 (median survival time, 25 months) at a single dialysis organization. Patients with adequate urea clearance and delivered dialysis session ≥240 and <240 minutes were pair-matched on interdialytic weight gain (n=1794), and patients with weight gain ≤3 and >3 kg were pair-matched on session length (n=2114); mortality associations were estimated separately.

RESULTS

Compared with delivered session length ≥240, session length <240 minutes was associated with increased all-cause mortality (adjusted hazard ratio [95% confidence interval], 1.32 [1.03 to 1.69]). Compared with weight gain ≤3, weight gain >3 kg was associated with increased mortality (1.29 [1.01 to 1.65]). The associations were consistent across strata of age, sex, weight, and weight gain and session length. Secondary analyses demonstrated dose-response relationships between both and mortality.

CONCLUSIONS

Among patients with adequate urea clearance, shorter dialysis session length and greater interdialytic weight gain are associated with increased mortality; thus, both are viable targets for directed intervention.

The relation between serum phosphorus levels and clinical outcomes after acute myocardial infarction

BACKGROUND

Elevated serum phosphorus levels have been linked with cardiovascular disease and mortality with conflicting results, especially in the presence of normal renal function.

METHODS

We studied the association between serum phosphorus levels and clinical outcomes in 1663 patients with acute myocardial infarction (AMI). Patients were categorized into 4 groups based on serum phosphorus levels (<2.50, 2.51-3.5, 3.51-4.50 and >4.50 mg/dL). Cox proportional-hazards models were used to examine the association between serum phosphorus and clinical outcomes after adjustment for potential confounders.

RESULTS

The mean follow up was 45 months. The lowest mortality occurred in patients with serum phosphorus between 2.5-3.5 mg/dL, with a multivariable-adjusted hazard ratio of 1.24 (95% CI 0.85-1.80), 1.35 (95% CI 1.05-1.74), and 1.75 (95% CI 1.27-2.40) in patients with serum phosphorus of <2.50, 3.51-4.50 and >4.50 mg/dL, respectively. Higher phosphorus levels were also associated with increased risk of heart failure, but not the risk of myocardial infarction or stroke. The effect of elevated phosphorus was more pronounced in patients with chronic kidney disease (CKD). The hazard ratio for mortality in patients with serum phosphorus >4.5 mg/dL compared to patients with serum phosphorus 2.50-3.50 mg/dL was 2.34 (95% CI 1.55-3.54) with CKD and 1.53 (95% CI 0.87-2.69) without CKD.

CONCLUSION

We found a graded, independent association between serum phosphorus and all-cause mortality and heart failure in patients after AMI. The risk for mortality appears to increase with serum phosphorus levels within the normal range and is more prominent in the presence of CKD.

Low plasma α-tocopherol concentrations and adverse clinical outcomes in diabetic hemodialysis patients

BACKGROUND AND OBJECTIVES

Trials with the antioxidant vitamin E have failed to show benefit in the general population. Considering the different causes of death in ESRD, this study investigated the association between plasma concentrations of α-tocopherol and specific clinical outcomes in diabetic hemodialysis patients.

DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS

In 1046 diabetic hemodialysis patients (participants of the German Diabetes and Dialysis Study), α-tocopherol was measured in plasma by reversed-phase HPLC. By Cox regression analyses, hazard ratios were determined for prespecified end points according to baseline plasma α-tocopherol levels: sudden death (n=134), myocardial infarction (n=172), stroke (n=89), combined cardiovascular events (n=398), fatal infection (n=107), and all-cause mortality (n=508).

RESULTS

Patients had a mean age of 66±8 years, and mean plasma α-tocopherol level was 22.8±9.6 µmol/L. Levels of α-tocopherol were highly correlated to triglycerides (r=0.63, P<0.001). Patients in the lowest α-tocopherol quartile had (in unadjusted analyses) a 79% higher risk of stroke and a 31% higher risk of all-cause mortality compared with patients in the highest quartile. The associations were attenuated after adjustment for confounders (hazard ratiostroke=1.56, 95% confidence interval=0.75-3.25; hazard ratiomortality=1.22, 95% confidence interval=0.89-1.69, respectively). There was no association between α-tocopherol and myocardial infarction, sudden death, or infectious death.

CONCLUSIONS

Plasma α-tocopherol concentrations were not independently associated with cardiovascular outcomes, infectious deaths, or all-cause mortality in diabetic hemodialysis patients. The lack of association can partly be explained by a confounding influence of malnutrition, which should be considered in the planning of trials to reduce cardiovascular risk in dialysis patients.