Dialysate Potassium, Dialysate Magnesium, and Hemodialysis Risk

Hyperkalemia burden and treatment patterns in Chinese patients on hemodialysis: final analysis of a prospective multicenter cohort study (PRECEDE-K)

OBJECTIVES

Patients with end-stage renal disease (ESRD) on hemodialysis (HD) are at risk for hyperkalemia (HK), associated with cardiac arrhythmia and sudden death. Data on the burden of HK and management techniques among HD patients in China are still scarce. This study assessed the treatment modalities, recurrence, and prevalence of HK in Chinese HD patients.

METHODS

In this prospective cohort study conducted from May 2021 to July 2022, patients aged ≥18 years who had ESRD and were on HD were enrolled from 15 centers in China (up to 6 months).

RESULTS

Overall, 600 patients were enrolled. At the baseline visit, mean (± standard deviation) urea reduction ratio was 68.0% ± 9.70 and Kt/V was 1.45 ± 0.496. Over 6 months, 453 (75.5%) patients experienced HK, of whom 356 (78.6%) recurred. Within 1, 2, 3, 4, 5, and 6 months, 203 (44.8%), 262 (57.8%), 300 (66.2%), 326 (72.0%), 347 (76.6%), and 356 (78.6%) patients had at least one HK recurrence event, respectively. The proportions of patients with ≥1, 2, 3, 4, 5, or 6 HK recurrence events were 356 (78.6%), 306 (67.5%), 250 (55.2%), 208 (45.9%), 161 (35.5%), and 110 (24.3%), respectively. Among the 453 patients who experienced HK, only 24 (5.3%) were treated with potassium binders: seven (1.5%) with sodium polystyrene sulfonate, 13 (2.9%) with calcium polystyrene sulfonate, and six (1.3%) with sodium zirconium cyclosilicate.

CONCLUSION

Since HK is a chronic illness, long-term care is necessary. Patients on HD should have effective potassium management on non-dialysis days, yet our real-world population rarely used potassium binders.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT04799067.

Association of the panimmune-inflammatory value (PIV) with all-cause and cardiovascular mortality in maintenance hemodialysis patients: a propensity score matching retrospective study

PURPOSE

The panimmune-inflammatory value (PIV) is a novel inflammatory indicator. However, its role in maintenance hemodialysis (MHD) remains unclear. Our goal was to explore the predictive value of PIV for cardiovascular and all-cause mortality in MHD patients.

METHODS

In this retrospective cohort study, 507 patients receiving MHD between November 2017 and December 2022 were enrolled. The PIV value was calculated as follows: neutrophil count × monocyte count × platelet count/lymphocyte count. Patients were divided into two groups on the basis of the median PIV. Propensity score matching (PSM) was used to adjust for imbalances in baseline information between groups. Kaplan‒Meier curves, Cox regression, the Fine‒Gray competing risk model, and restricted cubic spline (RCS) curves were used to analyze the relationship between PIV and mortality.

RESULTS

By the end of follow-up, 126 deaths had occurred, 91 of which were due to cardiovascular disease. The Kaplan‒Meier curves demonstrated that MHD patients with higher PIV levels had a poorer prognosis for all-cause death (p = 0.019). PIV levels were linked to all-cause death in multivariate Cox proportional risk regression (HR = 1.76; 95% CI 1.14, 2.72; p = 0.011). The Fine‒Gray model revealed a greater cumulative incidence of cardiovascular death in the higher PIV group (p = 0.035). PIV levels were linked to cardiovascular mortality in the Fine‒Gray competing risk model (HR = 2.06; 95% CI 1.25, 3.42; p = 0.005). The RCS revealed a nonlinear relationship between PIV and mortality risk (p < 0.05). Using 63 years of age as the threshold, we observed a multiplicative interaction effect between age and PIV for all-cause mortality (p = 0.006).

CONCLUSION

In MHD patients, PIV is an independent hazard factor for cardiovascular-related mortality and all-cause mortality.

Personalizing electrolytes in the dialysis prescription: what, why and how?

Maintenance hemodialysis patients suffer from multiple comorbidities and treatment-related complications. A personalized approach to hemodialysis prescription could reduce some of these burdens by preventing complications such as excessive changes in blood pressure, arrhythmias, post-dialysis fatigue and decreased quality of life. A patient-centered approach to dialysate electrolyte concentrations represents one such opportunity. In addition to modifications in dialysate electrolyte concentrations, consideration of individual factors such as patients' serum concentrations, medication profiles, nutritional status and comorbidities is critical to tailoring hemodialysis prescriptions to optimize patient outcomes. The development of personalized dialysis treatment depends on the collection of comprehensive patient data, advances in technology, resource allocation and patient involvement in decision-making. This review discusses how the treatment of maintenance hemodialysis patients could benefit from individualized changes in certain dialysis fluid components.

Multicentre, observational, retrospective cohort of hyperkalaemia burden at haemodialysis facility-level in China: the Visualize-HD study protocol

OBJECTIVES

Hyperkalaemia is a potentially life-threatening disorder in patients undergoing haemodialysis (HD). Excess mortality and hospitalisation have been associated with hyperkalaemia (HK) after the long (2-day) interdialytic interval (LIDI) in patients on thrice a week HD compared with the short (1-day) interdialytic interval. Moreover, not much research has been conducted in China on the descriptive epidemiology and management of HK among different HD centres. The aim of this study is to address this evidence gap by investigating the risk factors associated with HK clinical burden at the HD facility level, current HD centres management patterns, serum potassium management patterns, as well as the risk factors associated with crude mortality in China.

DESIGN

Multicentre, observational, retrospective cohort study.

SETTING

This study plans to enrol 300 HD centres across China. Haemodialysis centres having ≥100 patients on maintenance HD within 3 years before study initiation, with participation willingness, routine blood collection post-LIDI and death records will be included.

PARTICIPANTS

Patients aged ≥18 years and on chronic HD for ≥3 months will be considered eligible. Summary data about serum potassium, characteristics of patients, facility practice patterns will be collected at HD facility level and death records will be at the patient level.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome will be to examine the association between suspected risk factors and HK prevalence at HD facility level. Suspected risk factors include dialysis prescriptions and serum potassium testing frequency, characteristics of patients and related medication usage. The secondary outcome will be to determine the HK prevalence, serum potassium management pattern and risk factors associated with crude mortality. The primary and secondary outcomes will be analysed using regression models. Exploratory outcomes will further investigate the risk factors associated with serum potassium ≥6.0 and ≥6.5 mmol/L.

CONCLUSION

The study is expected to provide insights to improve dialysis practice patterns and understand the clinical burden of HK.

ETHICS AND DISSEMINATION

This study protocol was reviewed and approved by the Institutional Review Boards and Ethics Committee of Peking University People's Hospital (Approval number: 2020PHB324-01). The results will be disseminated through national and international presentations and peer-reviewed publications.

TRIAL REGISTRATION NUMBER

NCT05020717.

Hyperkalaemia prevalence and dialysis patterns in Chinese patients on haemodialysis: an interim analysis of a prospective cohort study (PRECEDE-K)

BACKGROUND

Hyperkalaemia is a known risk factor for cardiac arrhythmia and mortality in patients on haemodialysis. Despite standard adequate haemodialysis, hyperkalaemia is common in patients with end-stage renal disease (ESRD) at interdialytic intervals. Data on hyperkalaemia burden and its effects on dialysis patterns and serum potassium (sK) fluctuations in patients on haemodialysis in China remain limited. The prospective, observational cohort study (PRECEDE-K; NCT04799067) investigated the prevalence, recurrence, and treatment patterns of hyperkalaemia in Chinese patients with ESRD on haemodialysis.

METHODS

Six hundred adult patients were consecutively enrolled from 15 secondary and tertiary hospitals in China. In this interim analysis, we report the baseline characteristics of the cohort, the prevalence of predialysis hyperkalaemia (sK > 5.0 mmol/L), and the trends in serum-dialysate potassium gradient and intradialytic sK shift at Visit 1 (following a long interdialytic interval [LIDI]).

RESULTS

At baseline, most patients (85.6%) received three-times weekly dialysis; mean duration was 4.0 h. Mean urea reduction ratio was 68.0% and Kt/V was 1.45; 60.0% of patients had prior hyperkalaemia (previous 6 months). At Visit 1, mean predialysis sK was 4.83 mmol/L, and 39.6% of patients had hyperkalaemia. Most patients (97.7%) received a dialysate potassium concentration of 2.0 mmol/L. The serum-dialysate potassium gradient was greater than 3 mmol/L for over 40% of the cohort (1- < 2, 2- < 3, 3- < 4, and ≥ 4 mmol/L in 13.6%, 45.1%, 35.7%, and 5.2% of patients, respectively; mean: 2.8 mmol/L). The intradialytic sK reduction was 1- < 3 mmol/L for most patients (0- < 1, 1- < 2, 2- < 3, and ≥ 3 mmol/L in 24.2%, 62.2%, 12.8%, and 0.9% of patients, respectively; mean: 1.4 mmol/L).

CONCLUSIONS

Hyperkalaemia after a LIDI was common in this real-world cohort of Chinese patients despite standard adequate haemodialysis, and led to large serum-dialysate potassium gradients and intradialytic sK shifts. Previous studies have shown hyperkalaemia and sK fluctuations are highly correlated with poor prognosis. Effective potassium-lowering treatments should be evaluated for the improvement of long-term prognosis through the control of hyperkalaemia and sK fluctuations.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT04799067.

DIALIZE China: A Phase IIIb, Randomized, Placebo-Controlled Study to Reduce Predialysis Hyperkalemia With Sodium Zirconium Cyclosilicate in Chinese Patients

PURPOSE

The DIALIZE China study (Reduce Incidence of Pre-Dialysis Hyperkalaemia With Sodium Zirconium Cyclosilicate in Chinese Subjects) (NCT04217590) evaluated sodium zirconium cyclosilicate (SZC) for the management of hyperkalemia in Chinese patients undergoing hemodialysis.

METHODS

In the double-blind, Phase IIIb DIALIZE China study, Chinese adults with kidney failure and predialysis hyperkalemia (predialysis serum potassium [sK+] concentration >5.4 mmol/L after the long interdialytic interval [LIDI] and >5.0 mmol/L after ≥1 short interdialytic interval) who were receiving hemodialysis 3 times weekly were randomized to placebo or SZC 5 g once daily on nondialysis days. Doses were titrated towards maintaining normokalemia for 4 weeks (titration period) in 5-g increments up to 15 g. Primary efficacy was the proportion of responders during the 4-week evaluation period following the titration period (ie, those with a predialysis sK+ of 4.0-5.0 mmol/L for at least 3 of 4 hemodialysis visits following the LIDI) who did not require urgent rescue therapy.

FINDINGS

Overall, 134 adults (mean [SD] age, 55 [11.3] years) were randomized to SZC or placebo (n = 67 each). There were significantly more responders with SZC (37.3%) versus placebo (10.4%; estimated odds ratio [OR] = 5.10; 95% CI, 1.90-15.12; P < 0.001). The probability of all predialysis sK+ concentrations being 3.5 to 5.5 mmol/L was significantly higher with SZC versus placebo (estimated OR = 6.41; 95% CI, 2.71-15.12; P < 0.001). A greater proportion of patients achieved an sK+ of 3.5 to 5.5 mmol/L on at least 3 of 4 LIDI visits during evaluation with SZC (73.1%) versus placebo (29.9%). Serious adverse events occurred in 9.1% and 11.9% of patients in the SZC and placebo groups, respectively.

IMPLICATIONS

SZC treatment for predialysis hyperkalemia is effective and well tolerated in Chinese patients with kidney failure receiving hemodialysis.

CLINICALTRIALS

gov identifier: NCT04217590.

Associations of Serum and Dialysate Potassium Concentrations With Incident Atrial Fibrillation in a Cohort Study of Older US Persons Initiating Hemodialysis for Kidney Failure

Introduction

Atrial fibrillation (AF) disproportionally affects persons on maintenance hemodialysis (HD). Associations of serum and dialysate potassium concentrations [K+] with AF incidence are poorly understood.

Methods

We conducted a cohort study using Medicare claims merged with clinical data from a dialysis provider to determine whether serum-[K+] and/or dialysate-[K+] independently associated with AF incidence. Persons insured by fee-for-service Medicare aged ≥67 years at dialysis initiation and free from diagnosed AF prior to day 120 of dialysis were eligible. Serum-[K+] and dialysate-[K+] were assessed in 30-day intervals and patients were followed-up with for AF incidence in subsequent 30-day intervals.

Results

During 2006 to 2011, 15,190 persons (mean age = 76.3 years) initiating HD had no prior AF diagnosis. Mean serum-[K+] was 4.5 mEq/l; dialysate-[K+] was 3 mEq/l in 34% and 2 mEq/l in 52% of patients. Followed-up over 21,907 person-years, 2869 persons had incident AF (incidence/100 person-years, 13.1 [95% confidence interval [CI], 12.6-13.6]). The multivariable-adjusted association of serum-[K+] with incident AF was J-shaped as follows: relative to a serum-[K+] of 4.5 mEq/l, lower serum-[K+] associated with increased AF risk, whereas confidence bands for higher serum-[K+] indicated no association. Dialysis against a dialysate-[K+] of 3 mEq/l versus 2 mEq/l independently associated with a 14% (95% CI, 5%-24%) lower incidence of AF. No effect modification between serum-[K+] and dialysate-[K+] was detected (P = 0.34).

Conclusion

Lower serum-[K+] was independently associated with incident AF whereas elevated serum-[K+] was not. The findings support adoption of dialysate solutions with a dialysate-[K+] of 3 mEq/l, regardless of patients' serum-[K+], and elimination of lower dialysate-[K+] solutions from practice. Clinical trials randomizing patients to different dialysate-[K+] are warranted to establish causality.

The effects of glucose-free and glucose-containing dialysate during dialysis in MHD patients: a prospective cross-over study

OBJECTIVE

To investigate the effects of glucose-free and glucose-containing dialysates during dialysis in maintenance hemodialysis (MHD) patients by the prospective cross-over study, and detect glucose control methods in MHD patients.

METHODS

A total of 66 MHD 18-75 years old patients in our hospital from Nov. 2019 to Mar. 2020 were recruited. All patients underwent HD with 4 hours per time, three times per week. Glucose-free dialysate (glucose-free group) and then 5.55 mmol/L glucose-containing dialysate (glucose-5.55 group) were used alternately in dialysis. The demographics and parameters of pre- and post-dialysis were recorded.

RESULTS

A total of 60 patients were analyzed, and 28 patients among them had type 2 diabetes. Serum glucose pre and post dialysis were 8.64 ± 4.18 mmol/L versus 5.74 ± 1.82 mmol/L (p < 0.01) in glucose-free dialysate, and 9.31 ± 4.89 mmol/L versus 7.80 ± 2.59 mmol/L (p < 0.01) in glucose-5.55 dialysate. The post-dialysis blood glucose of glucose-free group was lower than glucose-5.55 group (5.74 ± 1.82 vs 7.80 ± 2.59, p < 0.01). About 18 (30.00%) patients in glucose-free group and 1 patient (1.67%) in glucose-5.55 group whose blood glucose was lower than 4.44 mmol/L (p < 0.01). About 29 patients (48.33%) in glucose-free group and 17 patients (28.33%; p = 0.02) in glucose-5.55 group have hunger feeling. Serum sodium level in the glucose-free group was higher than that in Glucose-5.55 group (137.92 ± 1.64 vs 136.70 ± 1.64, p < 0.01). Post-dialysis blood glucose had no significant differences between patients not using diabetes-related medication (13 patients) and patients using diabetes-related medication (15 patients) in glucose-free group (7.13 ± 1.78 mmol/L vs 6.08 ± 2.84 mmol/L, p = 0.23) and glucose-5.55 group (9.22 ± 2.59 mmol/L vs 9.35 ± 2.88 mmol/L, p = 0.90).

CONCLUSIONS

Glucose-free and glucose-5.55 dialysate both decrease the blood glucose post-dialysis. Dialysates containing 5.55 mmol/L glucose can reduce the incidence of hypoglycemia and lower serum sodium, but have no effect on blood pressure during dialysis. Stopping insulin and oral anti-diabetic drugs once before dialysis may not affect the control of blood glucose.

Arrhythmia in chronic hemodialysis as a function of predialysis electrolytes and interdialytic interval

INTRODUCTION

People with end-stage renal disease on hemodialysis are at increased risk for death due to arrhythmia associated with the prolonged interdialytic interval that typically spans the weekend, with bradycardia being the arrhythmia most closely associated with sudden death. In this prospective observational study we assessed whether predialysis fluid and electrolytes values including hyperkalemia are risk factors for the arrhythmias associated with the prolonged interdialytic interval.

METHODS

Sixty patients on hemodialysis with a history of hyperkalemia underwent cardiac monitoring for 1 week. Arrhythmia frequency, average QTc interval, and average root mean square of successive differences (rMSSD) per 4-h period were reported. Predialysis electrolytes and electrocardiograms were collected prior to pre- and post-weekend dialysis sessions. Clinical variables were assessed for correlation with arrhythmias.

FINDINGS

Predialysis hyperkalemia occurred in 29 subjects and was more common at the post-weekend dialysis session. Bradycardia occurred in 11 subjects and increased before and during the post-weekend dialysis session, but was not correlated with any electrolyte or clinical parameter. Ventricular ectopy occurred in 50 subjects with diurnal variation unrelated to dialysis. Pre-dialysis prolonged QTc was common and not affected by interdialytic interval. Average QTc increased and rMSSD decreased during dialysis sessions and were not correlated with clinical parameters.

DISCUSSION

The results confirm that arrhythmias are prevalent in dialysis subjects with bradycardia particularly associated with the longer interdialytic interval; EKG markers of arrhythmia risk are increased during dialysis independent of interdialytic interval. Larger sample size and/or longer recording may be necessary to identify the clinical parameters responsible.

Hyperkalemia in Chronic Kidney Disease: Links, Risks and Management

Hyperkalemia is a common clinical problem with potentially fatal consequences. The prevalence of hyperkalemia is increasing, partially due to wide-scale utilization of prognostically beneficial medications that inhibit the renin-angiotensin-aldosterone-system (RAASi). Chronic kidney disease (CKD) is one of the multitude of risk factors for and associations with hyperkalemia. Reductions in urinary potassium excretion that occur in CKD can lead to an inability to maintain potassium homeostasis. In CKD patients, there are a variety of strategies to tackle acute and chronic hyperkalemia, including protecting myocardium from arrhythmias, shifting potassium into cells, increasing potassium excretion from the body, addressing dietary intake and treating associated conditions, which may exacerbate problems such as metabolic acidosis. The evidence base is variable but has recently been supplemented with the discovery of novel oral potassium binders, which have shown promise and efficacy in studies. Their use is likely to become widespread and offers another tool to the clinician treating hyperkalemia. Our review article provides an overview of hyperkalemia in CKD patients, including an exploration of relevant guidelines and nuances around management.

Course of Hyperkalemia in Patients on Hemodialysis

Background

Evidence of longitudinal serum potassium (sK⁺) concentrations in hyperkalemic hemodialysis patients is sparse.

Objective

These post hoc analyses of the placebo arm of the phase 3b DIALIZE study (NCT03303521) explored the course of hyperkalemia in hemodialysis patients receiving placebo.

Methods

In DIALIZE, 196 patients receiving hemodialysis three times weekly were randomized to placebo or sodium zirconium cyclosilicate 5 g starting dose once daily on nondialysis days for 8 weeks. In these post hoc analyses of placebo patients overall (n = 86) and by predialysis sK⁺ subgroups at randomization <5.5 mmol/L, 5.5 to <6.0 mmol/L, 6.0 to <6.5 mmol/L, and ≥6.5 mmol/L, we assessed mean predialysis sK⁺ concentration by visit and the proportions of patients with mean predialysis sK⁺ ranges of 4.0–5.0 and 4.0–5.5 mmol/L by visit.

Results

In placebo patients, the mean predialysis sK⁺ concentration at randomization was 5.9 mmol/L, and 5.8 mmol/L at the end of the study (day 57). For placebo patients overall and across all predialysis sK⁺ subgroups, the mean predialysis sK⁺ concentration remained ≥5.0 mmol/L for all visits over 8 weeks. Overall, 7–21% and 27–62% of placebo patients had predialysis sK⁺ ranges of 4.0–5.0 and 4.0–5.5 mmol/L, respectively, at any visit. The proportions of placebo patients with either predialysis sK⁺ range were greatest for those who were least hyperkalemic (<5.5 mmol/L) and generally decreased with increasing predialysis sK⁺ concentration.

Conclusions

Patients receiving placebo and hemodialysis maintained high predialysis sK⁺ concentrations over 8 weeks following a hyperkalemic event. Most placebo patients remained hyperkalemic and may be at continued risk of adverse events.

Strategies for optimizing urea removal to enable portable kidney dialysis: A reappraisal

BACKGROUND

Portable hemodialysis has the potential to improve health outcomes and quality of life for patients with kidney failure at reduced costs. Urea removal, required for dialysate regeneration, is a central function of any existing/potential portable dialysis device. Urea in the spent dialysate coexists with non-urea uremic toxins, nutrients, and electrolytes, all of which will interfere with the urea removal efficiency, regardless of whether the underlying urea removal mechanism is based on urease conversion, direct urea adsorption, or oxidation. The aim of the current review is to identify the amount of the most prevalent chemicals being removed during a single dialysis session and evaluate the potential benefits of an urea-selective membrane for portable dialysis.

METHODS

We have performed a literature search using Web of Science and PubMed databases to find available articles reporting (or be able to calculate from blood plasma concentration) > 5 mg of individually quantified solutes removed during thrice-weekly hemodialysis sessions. If multiple reports of the same solute were available, the reported values were averaged, and the geometric mean of standard deviations was taken. Further critical literature analysis of reported dialysate regeneration methods was performed using Web of Science and PubMed databases.

RESULTS

On average, 46.0 g uremic retention solutes are removed in a single conventional dialysis session, out of which urea is only 23.6 g. For both urease- and sorbent-based urea removal mechanisms, amino acids, with 7.7 g removal per session, could potentially interfere with urea removal efficiency. Additionally for the oxidation-based urea removal system, plentiful nutrients such as glucose (24.0 g) will interfere with urea removal by competition. Using a nanofiltration membrane between dialysate and oxidation unit with a molecular weight cutoff (MWCO) of ~200 Da, 67.6 g of non-electrolyte species will be removed in a single dialysis session, out of which 44.0 g are non-urea molecules. If the membrane MWCO is further decreased to 120 Da, the mass of non-electrolyte non-urea species will drop to 9.3 g. Reverse osmosis membranes have been shown to be both effective at blocking the transport of non-urea species (creatinine for example with ~90% rejection ratio), and permissive for urea transport (~20% rejection ratio), making them a promising urea selective membrane to increase the efficiency of the oxidative urea removal system.

CONCLUSIONS

Compiled are quantified solute removal amounts greater than 5 mg per session during conventional hemodialysis treatments, to act as a guide for portable dialysis system design. Analysis shows that multiple chemical species in the dialysate interfere with all proposed portable urea removal systems. This suggests the need for an additional protective dialysate loop coupled to urea removal system and an urea-selective membrane.

Hidden risks associated with conventional short intermittent hemodialysis: A call for action to mitigate cardiovascular risk and morbidity

The development of maintenance hemodialysis (HD) for end stage kidney disease patients is a success story that continues to save many lives. Nevertheless, intermittent renal replacement therapy is also a source of recurrent stress for patients. Conventional thrice weekly short HD is an imperfect treatment that only partially corrects uremic abnormalities, increases cardiovascular risk, and exacerbates disease burden. Altering cycles of fluid loading associated with cardiac stretching (interdialytic phase) and then fluid unloading (intradialytic phase) likely contribute to cardiac and vascular damage. This unphysiologic treatment profile combined with cyclic disturbances including osmotic and electrolytic shifts may contribute to morbidity in dialysis patients and augment the health burden of treatment. As such, HD patients are exposed to multiple stressors including cardiocirculatory, inflammatory, biologic, hypoxemic, and nutritional. This cascade of events can be termed the dialysis stress storm and sickness syndrome. Mitigating cardiovascular risk and morbidity associated with conventional intermittent HD appears to be a priority for improving patient experience and reducing disease burden. In this in-depth review, we summarize the hidden effects of intermittent HD therapy, and call for action to improve delivered HD and develop treatment schedules that are better tolerated and associated with fewer adverse effects.

Potassium responses to sodium zirconium cyclosilicate in hyperkalemic hemodialysis patients: post-hoc analysis of DIALIZE

BACKGROUND

Sodium zirconium cyclosilicate (SZC) is an effective and well-tolerated treatment for hyperkalemia in maintenance hemodialysis patients. In post-hoc analyses of the phase 3b DIALIZE study, we examined the spectrum of potassium responses to SZC.

METHODS

Post-hoc analyses with SZC and placebo included: the number of long interdialytic interval (LIDI) visits during the 4-week evaluation period where patients attained pre-dialysis serum potassium (sK⁺) concentrations of 4.0-5.0 and 4.0-5.5 mmol/L; potassium gradient (the difference between pre-dialysis sK⁺ and dialysate potassium) at days 36, 43, 50, and 57, and change from baseline to the end of treatment (EOT) using categories of potassium gradient (1 to < 2, 2 to < 3, 3 to < 4, and ≥ 4 mmol/L).

RESULTS

A greater proportion of patients achieved the ranges of pre-dialysis sK⁺ concentration with SZC versus placebo for ≥1, ≥ 2, ≥ 3, and 4 LIDI visits over 4 weeks; 23.7 and 48.5% of patients in the SZC group achieved pre-dialysis sK⁺ concentrations of 4.0-5.0 and 4.0-5.5 mmol/L, respectively, at all 4 LIDI visits. Baseline mean potassium gradient was similar with SZC and placebo. At day 57, mean (standard deviation) potassium gradient was 2.78 (0.08) mmol/L with SZC and 3.52 (0.08) mmol/L with placebo; mean difference (95% confidence interval) was - 0.74 mmol/L (- 0.97 to - 0.52). A greater reduction in potassium gradient category from baseline towards lower-risk categories at EOT was observed with SZC versus placebo.

CONCLUSIONS

These analyses expand our knowledge of the spectrum of potassium responses with SZC in hyperkalemic hemodialysis patients.

TRIAL REGISTRATION

NCT03303521 .

Choices in hemodialysis therapies: variants, personalized therapy and application of evidence-based medicine

The extent of removal of the uremic toxins in hemodialysis (HD) therapies depends primarily on the dialysis membrane characteristics and the solute transport mechanisms involved. While designation of ‘flux’ of membranes as well toxicity of compounds that need to be targeted for removal remain unresolved issues, the relative role, efficiency and utilization of solute removal principles to optimize HD treatment are better delineated. Through the combination and intensity of diffusive and convective removal forces, levels of concentrations of a broad spectrum of uremic toxins can be lowered significantly and successfully. Extended clinical experience as well as data from several clinical trials attest to the benefits of convection-based HD treatment modalities. However, the mode of delivery of HD can further enhance the effectiveness of therapies. Other than treatment time, frequency and location that offer clinical benefits and increase patient well-being, treatment- and patient-specific criteria may be tailored for the therapy delivered: electrolytic composition, dialysate buffer and concentration and choice of anticoagulating agent are crucial for dialysis tolerance and efficacy. Evidence-based medicine (EBM) relies on three tenets, i.e. clinical expertise (i.e. doctor), patient-centered values (i.e. patient) and relevant scientific evidence (i.e. science), that have deviated from their initial aim and summarized to scientific evidence, leading to tyranny of randomized controlled trials. One must recognize that practice patterns as shown by Dialysis Outcomes and Practice Patterns Study and personalization of HD care are the main driving force for improving outcomes. Based on a combination of the three pillars of EBM, and particularly on bedside patient–clinician interaction, we summarize what we have learned over the last 6 decades in terms of best practices to improve outcomes in HD patients. Management of initiation of dialysis, vascular access, preservation of kidney function, selection of biocompatible dialysers and use of dialysis fluids of high microbiological purity to restrict inflammation are just some of the approaches where clinical experience is vital in the absence of definitive scientific evidence. Further, HD adequacy needs to be considered as a broad and multitarget approach covering not just the dose of dialysis provided, but meeting individual patient needs (e.g. fluid volume, acid–base, blood pressure, bone disease metabolism control) through regular assessment—and adjustment—of a series of indicators of treatment efficiency. Finally, in whichever way new technologies (i.e. artificial intelligence, connected health) are embraced in the future to improve the delivery of dialysis, the human dimension of the patient–doctor interaction is irreplaceable. Kidney medicine should remain ‘an art’ and will never be just ‘a science’.

Terapia de reemplazo renal, una alternativa para la calidad de vida de los pacientes

La enfermedad renal crónica es una patología causada por la pérdida del funcionamiento del riñón con una filtración glomerular alterada por más de tres meses, por lo que es necesario recibir terapia de reemplazo renal consistente en la sustitución de esta función mediante la extracción de líquidos de la sangre y su filtración a través de membranas semipermeables, en especial para mantener la homeostasis mediante la eliminación de sustancias tóxicas nitrogenadas y desechos acumulados. Estos procedimientos y en particular la hemodiálisis pueden presentar diversas complicaciones debido a que son procesos invasivos. Cabe mencionar que los pacientes en terapia de reemplazo presentan una disminución de la calidad de vida sobre todo a nivel físico y psicológico, a costa de mantener una mejor condición de su salud renal.

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.

Hyperkalemia in patients undergoing hemodialysis: its pathophysiology and management

Potassium is a major intracellular cation in the body, regulating membrane potential of excitable cells, such as cardiomyocytes and skeletal muscle cells. Because the kidney plays a critical role in controlling potassium balance, the elevation in serum potassium levels is one of the most common complications in patients with maintenance hemodialysis (MHD). In addition to reduced renal potassium excretion, the alteration in body potassium distribution owing to comorbid conditions may also contribute to dyskalemia. Besides potassium elimination through hemodialysis in MHD patients, accumulating data indicate the potential importance of extra‐renal elimination involving the gastrointestinal system, which can be affected by the inhibitors of the renin‐angiotensin‐aldosterone system. In this article, the literature on potassium physiology in MHD patients is reviewed with an emphasis on the changes from individuals with normal kidney function. This article also summarizes the findings of recent studies on dietary control, dialysate prescription, and pharmacological therapy.

Consensus-Based Recommendations for the Management of Hyperkalemia in the Hemodialysis Setting

Hyperkalemia (serum K⁺ >5.0 mmol/L) is commonly observed among patients receiving maintenance hemodialysis and associated with increased risk of cardiac arrhythmias. Current international guidelines may not reflect the latest evidence on managing hyperkalemia in patients undergoing hemodialysis, and there is a lack of high-quality published studies in this area. This consensus guideline aims to provide recommendations in relation to clinical practice. Available published evidence was evaluated through a systematic literature review, and the nominal group technique was used to develop consensus recommendations from a panel of experienced nephrologists, covering monitoring, dietary restrictions, prescription of K⁺ binders, and concomitant prescription of renin-angiotensin-aldosterone system inhibitors. Recent studies have shown that K⁺ binders reduce the incidence of hyperkalemia, but further evidence is needed in areas including whether reduced-K⁺ diets or treatment with K⁺ binders improve patient-centered outcomes. Treatment of hyperkalemia in the hemodialysis setting is complex, and decisions need to be tailored for individual patients.

Hyperkalemia excursions are associated with an increased risk of mortality and hospitalizations in hemodialysis patients

BACKGROUND

Hyperkalemia is common among hemodialysis (HD) patients and has been associated with adverse clinical outcomes. Previous studies considered a single serum potassium (K) measurement or time-averaged values, but serum K excursions out of the target range may be more reflective of true hyperkalemia events. We assessed whether hyperkalemia excursions lead to an elevated risk of adverse clinical outcomes.

METHODS

Using data from 21 countries in Phases 4-6 (2009-18) of the Dialysis Outcomes and Practice Patterns Study (DOPPS), we investigated the associations between peak serum K level, measured monthly predialysis, over a 4-month period ('peak K') and clinical outcomes over the subsequent 4 months using Cox regression, adjusted for potential confounders.

RESULTS

The analysis included 62 070 patients contributing a median of 3 (interquartile range 2-6) 4-month periods. The prevalence of hyperkalemia based on peak K was 58% for >5.0, 30% for >5.5 and 12% for >6.0 mEq/L. The all-cause mortality hazard ratio for peak K (reference ≤5.0 mEq/L) was 1.15 [95% confidence interval (CI) 1.09, 1.21] for 5.1-5.5 mEq/L, 1.19 (1.12, 1.26) for 5.6-6.0 mEq/L and 1.33 (1.23, 1.43) for >6.0 mEq/L. Results were qualitatively consistent when analyzing hospitalizations and a cardiovascular composite outcome.

CONCLUSIONS

Among HD patients, we identified a lower K threshold (peak K 5.1-5.5 mEq/L) than previously reported for increased risk of hospitalization and mortality, with the implication that a greater proportion (>50%) of the HD population may be at risk. A reassessment of hyperkalemia severity ranges is needed, as well as an exploration of new strategies for effective management of chronic hyperkalemia.

A high magnesium concentration in citrate dialysate prevents oxidative stress and damage in human monocytes in vitro

BACKGROUND

The use of dialysis fluids (DFs) during haemodialysis has been associated with increased oxidative stress and reduced serum magnesium (Mg) levels, contributing to chronic inflammation. Since the role of Mg in modulating immune function and reducing oxidative stress has been demonstrated, the aim of this study was to characterize in vitro whether increasing the Mg concentration in DFs could protect immune cells from oxidative stress and damage.

METHODS

The effect of citrate [citrate dialysis fluid (CDF), 1 mM] or acetate [acetate dialysis fluid (ADF), 3 mM] dialysates with low (0.5 mM; routinely used) or high (1 mM, 1.25 mM and 2 mM) Mg concentrations was assessed in THP-1 human monocytes. The levels of reactive oxygen species (ROS), malondialdehyde (MDA) and oxidized/reduced (GSSG/GSH) glutathione were quantified under basal and inflammatory conditions (stimulation with lipopolysaccharide, LPS).

RESULTS

The increase of Mg in CDF resulted in a significant reduction of ROS production under basal and inflammatory conditions (extremely marked in 2 mM Mg; P < 0.001). These effects were not observed in ADF. Interestingly, in a dose-dependent manner, high Mg doses in CDF reduced oxidative stress in monocytes under both basal and inflammatory conditions. In fact, 2 mM Mg significantly decreased the levels of GSH, GSSG and MDA and the GSSG/GSH ratio in relation to 0.5 mM Mg.

CONCLUSIONS

CDF produces lower oxidative stress than ADF. The increase of Mg content in DFs, especially in CDF, could have a positive and protective effect in reducing oxidative stress and damage in immune cells, especially under inflammatory conditions.

Updates on hemodialysis techniques with a common denominator: The personalization of the dialytic therapy

Hemodialysis (HD) is a life-saving therapy for patients with end-stage renal disease. In dialyzed patients, the prevalence of multi-morbidity is rising driven by various factors, such as the population aging, the incomplete correction of uremia, and the side effects of the dialysis therapy itself. Each dialyzed patient has their own specific clinical and biochemical problems. It is therefore unthinkable that the same dialysis procedure can be able to meet the needs of every patient on chronic dialysis. We have very sophisticated dialysis machines and different dialysis techniques and procedures beyond conventional HD, such as hemodiafiltration (HDF) with pre- and post-dilution, acetate-free biofiltration (AFB), hemofiltration (HF), and expanded HD. Each of these techniques has its own specific characteristics. To solve some intradialytic clinical issues, such as arterial hypotension and arrhythmias, we have biofeedback systems with automatic regulation of the blood volume, body temperature, arterial pressure, as well as potassium profiling techniques in the dialysis bath. New technical innovations, such as citrate-containing dialysate or heparin-coated membranes, could reduce the risk of bleeding. To better address to patient needs, the strengths and weaknesses of each of these systems must be well-known, in order to have a personalized dialysis prescription for each patient.

Monitoring blood potassium concentration in hemodialysis patients by quantifying T-wave morphology dynamics

We investigated the ability of time-warping-based ECG-derived markers of T-wave morphology changes in time ([Formula: see text]) and amplitude ([Formula: see text]), as well as their non-linear components ([Formula: see text] and [Formula: see text]), and the heart rate corrected counterpart ([Formula: see text]), to monitor potassium concentration ([Formula: see text]) changes ([Formula: see text]) in end-stage renal disease (ESRD) patients undergoing hemodialysis (HD). We compared the performance of the proposed time-warping markers, together with other previously proposed [Formula: see text] markers, such as T-wave width ([Formula: see text]) and T-wave slope-to-amplitude ratio ([Formula: see text]), when computed from standard ECG leads as well as from principal component analysis (PCA)-based leads. 48-hour ECG recordings and a set of hourly-collected blood samples from 29 ESRD-HD patients were acquired. Values of [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] were calculated by comparing the morphology of the mean warped T-waves (MWTWs) derived at each hour along the HD with that from a reference MWTW, measured at the end of the HD. From the same MWTWs [Formula: see text] and [Formula: see text] were also extracted. Similarly, [Formula: see text] was calculated as the difference between the [Formula: see text] values at each hour and the [Formula: see text] reference level at the end of the HD session. We found that [Formula: see text] and [Formula: see text] showed higher correlation coefficients with [Formula: see text] than [Formula: see text]-Spearman's ([Formula: see text]) and Pearson's (r)-and [Formula: see text]-Spearman's ([Formula: see text])-in both SL and PCA approaches being the intra-patient median [Formula: see text] and [Formula: see text] in SL and [Formula: see text] and [Formula: see text] in PCA respectively. Our findings would point at [Formula: see text] and [Formula: see text] as the most suitable surrogate of [Formula: see text], suggesting that they could be potentially useful for non-invasive monitoring of ESRD-HD patients in hospital, as well as in ambulatory settings. Therefore, the tracking of T-wave morphology variations by means of time-warping analysis could improve continuous and remote [Formula: see text] monitoring of ESRD-HD patients and flagging risk of [Formula: see text]-related cardiovascular events.

Cardiac arrhythmia during early-week and mid-week dialysis in hemodialysis patients

Data on cardiac arrhythmia and electrolyte changes during the dialysis cycle have been limited. Fifty-two hemodialysis (HD) patients underwent 48-h Holter monitoring during early-week and mid-week HD sessions. Pre-HD and post-HD blood samples were collected in both HD sessions. The 48-h Holter data were divided into five phases: (1) 4-h during the early-week HD (HD1), (2) 12-h post-HD1, (3) 16-h period between Phases 2 and 4 (used as the patient's baseline electrocardiography [ECG]), (4) 12-h pre-HD2 phase, and (5) 4-h during the mid-week HD (HD2). The patients' mean age was 68.54 ± 13.37 years. We found that the dialysate-to-serum[K] gradient and changes of S[K] were significantly higher in HD1 than in HD2, as well as changes of S[Mg]. There were no significant ECG changes during the 4-h HD1 and HD2 when compared with the baseline ECG. Phase 2 of Holter ECG was the most common phase that showed significant changes (increased QT interval dispersion (QTD), increased ventricular events, increased number of premature ventricular contractions, ST elevation and ST depression), which was contributed from the dialysate[K] 2 mmol/L subgroup, but not the dialysate[K] 3 mmol/L subgroup. In the subgroup of patients with a high ultrafiltration rate (UFR; mean UFR ≥10 mL/kg/h), there were significantly increased ventricular events and ST-segment changes in Phase 2. In conclusion, ECG changes were associated with the dialysis cycle, significantly in the 12-h after early-week HD sessions. These may be associated with low dialysate[K] or high dialysate-to-S[K] gradient, high ultrafiltration rate and duration of the interdialytic interval.

Dyselectrolytemia-management and implications in hemodialysis (Review)

Hemodialysis is a method for the renal replacement therapy followed by series of acute and chronic complications. Dyselectrolytemia appears in patients undergoing dialysis through mechanisms related to the chronic kidney disease and/or to the dialysis therapy and for this group of patients it is associated with an increase of morbidity and mortality. The dialysate has a standard composition, which can be modified according to the patient's characteristics. During hemodialysis patients are exposed to 18,000-36.000 litres of water/year, and the water purity along with the biochemical composition of the dialysate are essential. The individualization of the dialysis prescription is recommended for each patient and it has an important role in preventing the occurrence of dyselectrolyemia. The individualization of the treatment prescription according to the blood constants of each patient is the prerogative of the nephrologist and the association of the electrolyte imbalances with the patients cardiovascular mortality explains the importance of paying special attention to them.

Dialysis-Induced Cardiovascular and Multiorgan Morbidity

Hemodialysis has saved many lives, albeit with significant residual mortality. Although poor outcomes may reflect advanced age and comorbid conditions, hemodialysis per se may harm patients, contributing to morbidity and perhaps mortality. Systemic circulatory "stress" resulting from hemodialysis treatment schedule may act as a disease modifier, resulting in a multiorgan injury superimposed on preexistent comorbidities. New functional intradialytic imaging (i.e., echocardiography, cardiac magnetic resonance imaging [MRI]) and kinetic of specific cardiac biomarkers (i.e., Troponin I) have clearly documented this additional source of end-organ damage. In this context, several factors resulting from patient-hemodialysis interaction and/or patient management have been identified. Intradialytic hypovolemia, hypotensive episodes, hypoxemia, solutes, and electrolyte fluxes as well as cardiac arrhythmias are among the contributing factors to systemic circulatory stress that are induced by hemodialysis. Additionally, these factors contribute to patients' symptom burden, impair cognitive function, and finally have a negative impact on patients' perception and quality of life. In this review, we summarize the adverse systemic effects of current intermittent hemodialysis therapy, their pathophysiologic consequences, review the evidence for interventions that are cardioprotective, and explore new approaches that may further reduce the systemic burden of hemodialysis. These include improved biocompatible materials, smart dialysis machines that automatically may control the fluxes of solutes and electrolytes, volume and hemodynamic control, health trackers, and potentially disruptive technologies facilitating a more personalized medicine approach.

A Higher Concentration of Dialysate Magnesium to Reduce the Frequency of Muscle Cramps: A Narrative Review

Purpose of review:

Strategies to mitigate muscle cramps are a top research priority for patients receiving hemodialysis. As hypomagnesemia is a possible risk factor for cramping, we reviewed the literature to better understand the physiology of cramping as well as the epidemiology of hypomagnesemia and muscle cramps. We also sought to review the evidence from interventional studies on the effect of oral and dialysate magnesium-based therapies on muscle cramps.

Sources of information:

Peer-reviewed articles.

Methods:

We searched for relevant articles in major bibliographic databases including MEDLINE and EMBASE. The methodological quality of interventional studies was assessed using a modified version of the Downs and Blacks criteria checklist.

Key findings:

The etiology of muscle cramps in patients receiving hemodialysis is poorly understood and there are no clear evidence-based prevention or treatment strategies. Several factors may play a role including a low concentration of serum magnesium. The prevalence of hypomagnesemia (concentration of <0.7 mmol/L) in patients receiving hemodialysis ranges from 10% to 20%. Causes of hypomagnesemia include a low dietary intake of magnesium, use of medications that inhibit magnesium absorption (eg, proton pump inhibitors), increased magnesium excretion (eg, high-dose loop diuretics), and a low concentration of dialysate magnesium. Dialysate magnesium concentrations of ≤0.5 mmol/L may be associated with a decrease in serum magnesium concentration over time. Preliminary evidence from observational and interventional studies suggests a higher dialysate magnesium concentration will raise serum magnesium concentrations and may reduce the frequency and severity of muscle cramps. However, the quality of evidence supporting this benefit is limited, and larger, multicenter clinical trials are needed to further determine if magnesium-based therapy can reduce muscle cramps in patients receiving hemodialysis. In studies conducted to date, increasing the concentration of dialysate magnesium appears to be well-tolerated and is associated with a low risk of symptomatic hypermagnesemia.

Limitations:

Few interventional studies have examined the effect of magnesium-based therapy on muscle cramps in patients receiving hemodialysis and most were nonrandomized, pre-post study designs.

Large potassium shifts during dialysis enhance cardiac repolarization instability

Background

Patients with end-stage kidney disease are at high risk for the development of arrhythmias and sudden cardiac death (SCD). This has been especially attributed to large potassium shifts during hemodialysis (HD), and malignant arrhythmias are closely linked to dysfunction of the autonomic nervous system. Nevertheless, there is still a lack of methods for risk stratification in these patients.

Methods

In the present pilot study we investigated changes of the novel ECG-based biomarker periodic repolarization dynamics (PRD) mirroring the effect of efferent sympathetic nervous activity on the ventricular myocardium in 18 patients undergoing routine hemodialysis. High-resolution ECGs were recorded throughout the dialysis and PRD values were calculated out of 30 min intervals at the start and the end of dialysis.

Results

We detected a clear correlation between the intradialytic potassium shift and the increase in PRD levels (Spearman correlation coefficient R = 0.62, p = 0.006). Patients with a potassium shift > 1 mmol/l showed significantly increased levels of PRD at the end of dialysis when compared to patients with potassium shifts ≤ 1.0 mmol/l [delta PRD 2.82 (IQR 2.13) vs. − 2.08 (IQR 3.60), p = 0.006]. Spearman analysis showed no significant correlation between PRD changes and fluid removal (R = − 0.23, p = 0.36).

Conclusions

We provide evidence that large potassium shifts during HD enhance sympathetic activity-associated repolarization instability. This could facilitate the occurrence of malignant arrhythmias, and PRD measurements might serve as a non-invasive monitoring tool in HD patients in future.

Intradialytic Hypotension and Cardiac Arrhythmias in Patients Undergoing Maintenance Hemodialysis: Results from the Monitoring in Dialysis Study

BACKGROUND AND OBJECTIVES

Patients receiving maintenance hemodialysis (HD) have a high incidence of cardiac events, including arrhythmia and sudden death. Intradialytic hypotension (IDH) is a common complication of HD and is associated with development of reduced myocardial perfusion, a potential risk factor for arrhythmia.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We analyzed data from the Monitoring in Dialysis study, which used implantable loop recorders to detect and continuously monitor electrocardiographic data from patients on maintenance HD (n=66 from the United States and India) over a 6-month period (n=4720 sessions). Negative binomial mixed effects regression was used to test the association of IDH₂₀ (decline in systolic BP >20 mm Hg from predialysis systolic BP) and IDH_0-20 (decline in systolic BP 0-20 mm Hg from predialysis systolic BP) with clinically significant arrhythmia (bradycardia≤40 bpm for ≥6 seconds, asystole≥3 seconds, ventricular tachycardia ≥130 bpm for ≥30 seconds, or patient-marked events) during HD.

RESULTS

The median age of participants was 58 (25th-75th percentile, 49-66) years; 70% were male; and 65% were from the United States. IDH occurred in 2251 (48%) of the 4720 HD sessions analyzed, whereas IDH_0-20 occurred during 1773 sessions (38%). The number of sessions complicated by least one intradialytic clinically significant arrhythmia was 27 (1.2%) where IDH₂₀ occurred and 15 (0.8%) where IDH_0-20 occurred. Participants who experienced IDH₂₀ (versus not) had a nine-fold greater rate of developing an intradialytic clinically significant arrhythmia (incidence rate ratio, 9.4; 95% confidence interval, 3.0 to 29.4), whereas IDH_0-20 was associated with a seven-fold higher rate (incidence rate ratio, 7.2; 95% confidence interval, 2.1 to 25.4).

CONCLUSIONS

IDH is common in patients on maintenance HD and is associated with a greater risk of developing intradialytic clinically significant arrhythmia.

Increasing the Magnesium Concentration in Various Dialysate Solutions Differentially Modulates Oxidative Stress in a Human Monocyte Cell Line

Oxidative stress is exacerbated in hemodialysis patients by several factors, including the uremic environment and the use of dialysis fluids (DFs). Since magnesium (Mg) plays a key role in modulating immune function and in reducing oxidative stress, we aimed to evaluate whether increasing the Mg concentration in different DFs could protect against oxidative stress in immunocompetent cells in vitro. Effect of ADF (acetate 3 mM), CDF (citrate 1 mM), and ACDF (citrate 0.8 mM + acetate 0.3 mM) dialysates with Mg at standard (0.5 mM) or higher (1, 1.25, and 2 mM) concentrations were assessed in THP-1 monocyte cultures. Reactive oxygen species (ROS) and malondialdehyde (MDA) levels were quantified under basal and uremic conditions (indoxyl sulfate (IS) treatment). Under uremic conditions, the three DFs with 0.5 mM Mg promoted higher ROS production and lipid damage than the control solution. However, CDF and ACDF induced lower levels of ROS and MDA, compared to that induced by ADF. High Mg concentration (1.25 and/or 2 mM) in CDF and ACDF protected against oxidative stress, indicated by reduced ROS and MDA levels compared to respective DFs with standard concentration of Mg. Increasing Mg concentrations in ADF promoted high ROS production and MDA content. Thus, an increase in Mg content in DFs has differential effects on the oxidative stress in IS-treated THP-1 cells depending on the dialysate used.

The renal replacement therapy landscape in 2030: reducing the global cardiovascular burden in dialysis patients

Despite the significant progress made in understanding chronic kidney disease and uraemic pathophysiology, use of advanced technology and implementation of new strategies in renal replacement therapy, the clinical outcomes of chronic kidney disease 5 dialysis patients remain suboptimal. Considering residual suboptimal medical needs of short intermittent dialysis, it is our medical duty to revisit standards of dialysis practice and propose new therapeutic options for improving the overall effectiveness of dialysis sessions and reduce the burden of stress induced by the therapy. Several themes arise to address the modifiable components of the therapy that are aimed at mitigating some of the cardiovascular risks in patients with end-stage kidney disease. Among them, five are of utmost importance and include: (i) enhancement of treatment efficiency and continuous monitoring of dialysis performances; (ii) prevention of dialysis-induced stress; (iii) precise handling of sodium and fluid balance; (iv) moving towards heparin-free dialysis; and (v) customizing electrolyte prescriptions. In summary, haemodialysis treatment in 2030 will be substantially more personalized to the patient, with a clear focus on cardioprotection, volume management, arrhythmia surveillance, avoidance of anticoagulation and the development of more dynamic systems to align the fluid and electrolyte needs of the patient on the day of the treatment to their particular circumstances.

Current Management of Hyperkalemia in Patients on Dialysis

Patients with end-stage renal disease (ESRD) on maintenance dialysis have a high risk of developing hyperkalemia, generally defined as serum potassium (K⁺) concentrations of >5.0 mmol/l, particularly those undergoing maintenance hemodialysis. Currently, the key approaches to the management of hyperkalemia in patients with ESRD are dialysis, dietary K⁺ restriction, and avoidance of medications that increase hyperkalemia risk. In this review, we highlight the issues and challenges associated with effective management of hyperkalemia in patients undergoing maintenance dialysis using an illustrative case presentation. In addition, we examine the potential nondialysis options for the management of these patients, including use of the newer K⁺ binder agents patiromer and sodium zirconium cyclosilicate, which may reduce the need for the highly restrictive dialysis diet, with its own implication on nutritional status in patients with ESRD, as well as reducing the risk of potentially life-threatening hyperkalemia.

Potassium Binders for Hyperkalemia in Chronic Kidney Disease-Diet, Renin-Angiotensin-Aldosterone System Inhibitor Therapy, and Hemodialysis

Hyperkalemia is a potentially life-threatening complication of chronic kidney disease (CKD). The management of CKD requires balancing the benefits of specific treatments, which may exacerbate the potential for hyperkalemia, with the risks of hyperkalemia itself. Renin-angiotensin-aldosterone system (RAAS) inhibitors, which slow CKD progression and improve cardiovascular outcomes, are often discontinued if hyperkalemia develops. Patients with hyperkalemia are frequently advised to restrict dietary potassium (K⁺), depriving these patients of many heart-healthy foods. Patients receiving hemodialysis are particularly susceptible to hyperkalemia during long interdialytic intervals, and managing this risk without causing hypokalemia can be challenging. Recently, 2 K⁺-binding agents were approved for the treatment of hyperkalemia: sodium zirconium cyclosilicate and patiromer. These agents offer alternatives to sodium polystyrene sulfonate, which is associated with serious gastrointestinal adverse effects. For this review, PubMed was searched for English-language articles published in 2014-2018 using the terms patiromer, sodium zirconium cyclosilicate, sodium polystyrene sulfonate, hyperkalemia, renin-angiotensin-aldosterone, diet, and dialysis. In randomized controlled studies of patients with hyperkalemia, sodium zirconium cyclosilicate and patiromer effectively reduced serum K⁺ and were generally well tolerated. Furthermore, patients in these studies could maintain RAAS inhibitor therapy and, in some studies, were not required to limit dietary K⁺. There may also be a role for these agents in preventing hyperkalemia in patients receiving hemodialysis. Thus, K⁺-binding agents may allow patients with CKD at risk for hyperkalemia to optimize RAAS inhibitor therapy, receive benefits of a K⁺-rich diet, and experience improved hemodialysis outcomes. Additional long-term studies are necessary to confirm these effects.

Association between Blood Potassium Level and Recovery of Postoperative Gastrointestinal Motility during Continuous Renal Replacement Therapy in Patient Undergoing Open Abdominal Surgery

Background

The aim of this study was to identify the blood potassium level beneficial to the postoperative recovery of gastrointestinal motility during continuous renal replacement therapy (CRRT) in patient undergoing open abdominal surgery.

Materials and Methods

538 critically ill patients after open abdominal surgery and receiving CRRT were retrospectively recruited as the study cohort. Demographic and clinical data were recorded along with an evaluation of the postoperative gastrointestinal motility.

Results

Correlation analysis was used to assess the correlation coefficient, and then the variables with correlation coefficient value less than 0.5 were included in the binary logistic regression model. Binary logistic regression model indicated that the postoperative blood potassium level was independently associated with the recovery of gastrointestinal motility (OR=0.109, 95% CI= 0.063 to 0.190, p<0.001). Based on the normal range of blood potassium level, we selected the cut-off point of blood potassium level via Weight of Evidence analysis, which was 4.00 mmol/L. Compared with the patients with insufficient blood potassium levels (plasma potassium concentration < 4.00 mmol/L), those with sufficient blood potassium levels (plasma potassium concentration≥ 4.00 mmol/L) conferred an increase in the rate of 4-day postoperative recovery of gastrointestinal motility (OR= 4.425, 95% CI = 2.933 to 6.667, p<0.001).

Conclusions

Maintaining the blood potassium concentrations at a relatively high level of the normal blood potassium range during CRRT would be beneficial to postoperative recovery of gastrointestinal motility.

Dialysis Prescription and Sudden Death

In the United States, end-stage renal disease patients receiving hemodialysis have an exceedingly high risk of sudden cardiac death (SCD), accounting for 29% of death events, likely relating to their uremic milieu, recurring exposure to fluid and electrolyte fluxes, and underlying cardiovascular pathology. Furthermore, epidemiologic studies have shown that SCD events, as well as mortality and hospitalizations, occur most frequently on the first dialysis day after the long interdialytic gap, suggesting that abrupt fluctuations in the accumulation and removal of electrolytes, fluid, and uremic toxins over the dialysis cycle may be contributory. Some population-based observational studies have suggested that lower dialysate potassium concentrations appear to be associated with a heightened risk of postdialysis cardiac arrest in hemodialysis patients, although the optimal serum-to-dialysate potassium gradient remains unclear. Some observational studies have suggested that low dialysate calcium concentrations and high serum-to-dialysate calcium gradients may predispose patients to SCD. There is ongoing controversy about an association between higher dialysate bicarbonate concentrations and higher risk of cardiac arrest, likely owing to confounding by indication. Some observational studies also have shown that large interdialytic weight gains, fluid retention, and high ultrafiltration rates are linked with higher risk of SCD and mortality. However, there remains considerable controversy regarding the pros and cons of designating a specific upper ultrafiltration limit with extended treatment times as a clinical practice measure, and further studies are needed to define the optimal tools, metrics, targets, and implementation measures for volume control in the hemodialysis population. In this review, we highlight the epidemiology and pathophysiology of how specific aspects of the hemodialysis procedure may relate to the risk of SCD, as well as preventative strategies and future research directions that can address this risk.

Update on Chronic Kidney Disease Mineral and Bone Disorder in Cardiovascular Disease

Chronic kidney disease mineral and bone disorder (MBD) encompasses changes in mineral ion and vitamin D metabolism that are widespread in the setting of chronic kidney disease and end-stage renal disease. MBD components associate with cardiovascular disease in many epidemiologic studies. Through impacts on hypertension, activation of the renin-angiotensin-aldosterone system, vascular calcification, endothelial function, and cardiac remodeling and conduction, MBD may be a direct and targetable cause of cardiovascular disease. However, assessment and treatment of MBD is rife with challenges owing to biological tensions between its many components, such as calcium and phosphorus with their regulatory hormones fibroblast growth factor 23 and parathyroid hormone; fibroblast growth factor 23 with its co-receptor klotho; and vitamin D with control of calcium and phosphorus. These complex interactions between MBD components hinder the simple translation to clinical trials, which ultimately are needed to prove the benefits of treating MBD. Deeper investigation using precision medicine tools and principles, including genomics and individualized risk assessment and therapy, may help move the field closer toward clinical applications. This review provides a high-level overview of conventional and precision epidemiology in MBD, potential mechanisms of cardiovascular disease pathogenesis, and guiding therapeutic principles for established and emerging treatments.

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.

Dialysate potassium concentration: Should mass balance trump electrophysiology?

Nephrologists are faced with a difficult dilemma in choosing the ideal dialysis prescription to maintain neutral potassium mass balance. Should potassium mass balance goals prioritize the normalization of serum potassium levels using low potassium dialysate at the expense of provoking intradialytic arrhythmias, or should mass balance goals favor permissive hyperkalemia using higher dialysate potassium to avoid rapid intradialytic fluxes at the risk of more interdialytic arrhythmias? This review examines the factors that determine potassium mass balance among HD patients, the relationships between serum and dialysate potassium levels and outcomes, and concludes by examining currently available approaches to reducing risk of arrhythmias while managing potassium mass balance.

Dialysate Potassium and Mortality in a Prospective Hemodialysis Cohort

BACKGROUND

Studies examining the association of dialysate potassium concentration and mortality in hemodialysis patients show conflicting findings. We hypothesized that low dialysate potassium concentrations are associated with higher mortality, particularly in patients with high pre-dialysis serum potassium concentrations.

METHODS

We evaluated 624 hemodialysis patients from the prospective Malnutrition, Diet, and Racial Disparities in Kidney Disease study recruited from 16 outpatient dialysis facilities over 2011-2015 who underwent protocolized collection of dialysis treatment characteristics every 6 months. We examined the association of dialysate potassium concentration, categorized as 1, 2, and 3 mEq/L, with all-cause mortality risk in the -overall cohort, and stratified by pre-dialysis serum potassium (< 5 vs. ≥5 mEq/L) using case-mix adjusted Cox models.

RESULTS

In baseline analyses, dialysate potassium concentrations of 1 mEq/L were associated with higher mortality, whereas concentrations of 3 mEq/L were associated with similar mortality in the overall cohort (reference: 2 mEq/L): adjusted hazard ratios (aHRs; 95% CI) 1.70 (1.01-2.88) and 0.95 (0.64-1.39), respectively. In analyses stratified by serum potassium, baseline dialysate potassium concentrations of 1 mEq/L were associated with higher mortality in patients with serum potassium ≥5 mEq/L but not in those with serum potassium < 5 mEq/L: aHRs (95% CI) 2.87 (1.51-5.46) and 0.74 (0.27-2.07), respectively (p interaction = 0.04). These findings were robust with incremental adjustment for serum potassium, potassium-binding resins, and potassium-modifying medications.

CONCLUSION

Low (1 mEq/L) dialysate potassium -concentrations were associated with higher mortality, particularly in hemodialysis patients with high pre-dialysis serum potassium. Further studies are needed to identify therapeutic strategies that mitigate inter-dialytic serum potassium accumulation and subsequent high dialysate serum potassium gradients in this population.