Effects of frequent hemodialysis on blood pressure: Results from the randomized frequent hemodialysis network trials

The relative potential contribution of volume load and vascular mechanisms to hypertension in non-dialysis and dialysis chronic kidney disease patients

Background

Hypertension is highly prevalent and particularly difficult to treat adequately in patients with chronic kidney disease (CKD). The relative contribution of volume overload and vascular mechanisms to blood pressure measures in CKD and whether these effects differ in non-dialysis compared to dialysis patients is unknown.

Methods

We determined the potential impact of volume load (stroke volume) and vascular mechanisms (inverse of total arterial compliance (inv TAC) and systemic vascular resistance (SVR)) on mean and brachial and aortic systolic blood pressures in 67 non-dialysis and 48 dialysis chronic kidney disease (CKD) patients. Relationships were determined in confounder adjusted regression models.

Results

Stroke volume (p value = 0.003) was more strongly associated with mean arterial pressure than SVR (p value = 0.9) (p value for difference = 0.03). When stroke volume and SVR were entered in the same regression model (model R2 = 0.324), they contributed equally to the variation in mean arterial pressure (p value for difference = 0.5). Stroke volume (p value ≤ 0.002) and inv TAC (p value ≤ 0.001) contributed equally to the variation in systolic pressures (p value for difference ≥ 0.9). When stroke volume and inv TAC were entered in the same regression model (model R2 = 0.752 to 0.765), they contributed equally to the variation in systolic blood pressures (p value for difference = 0.7). Stroke volume, TAC and SVR were similar (p value ≥ 0.5) and associated to the same extent with blood pressure measures in non-dialysis and dialysis CKD patients (p value for difference ≥ 0.1). In receiver operator characteristic curve analysis, elevated systolic blood pressure was determined by stroke volume (p value = 0.005) and inv TAC (p value = 0.03) but not SVR (p value = 0.8). The calculated power of the study was 0.999 based on α = 0.05.

Conclusions

The present investigation suggests that both volume load and vascular mechanisms should be considered in the management of hypertension among patients with CKD. The extent and relative potential impact of volume load and vascular mechanisms on blood pressure measures are as large in non-dialysis compared to dialysis CKD patients.

Home-Based Dialysis: A Primer for the Internist

Home-based dialysis modalities offer both clinical and practical advantages to patients. The use of the home-based modalities, peritoneal dialysis and home hemodialysis, has been increasing over the past decade after a long period of decline. Given the increasing frequency of use of these types of dialysis, it is important for clinicians to be familiar with how these types of dialysis are performed and key clinical aspects of care related to their use in patients with end-stage kidney disease.

Home Dialysis in North America: The Current State

There is widespread interest in expanding the uptake of home dialysis in North America. Although kidney transplantation should be the preferred option in eligible patients, home hemodialysis (HD) and peritoneal dialysis (PD) offer cost-effective options for KRT. In this review, the motivation for promoting home dialysis is presented, and the literature supporting it is critically reviewed. Randomized comparisons of home HD and PD with in-center HD have been challenging to conduct and provide only limited information. Nonrandomized studies are heterogeneous in their design and have often yielded conflicting results. They are prone to bias, and this must be carefully considered when evaluating this literature. Home modalities seem to have equivalent clinical outcomes and quality of life when compared with in-center HD. However, the cost of providing home therapies, particularly PD, is lower than conventional, in-center HD. Measures of home dialysis utilization, the philosophy behind their measurement, and important factors to consider when interpreting them are discussed. The importance of understanding measures of home dialysis utilization in the context of rates of kidney failure, the proportion of individuals who opt for conservative care, and rates of kidney transplantation is highlighted, and a framework for proposing targets is presented, using PD as an example.

Interventions for fatigue in people with kidney failure requiring dialysis

BACKGROUND

Fatigue is a common and debilitating symptom in people receiving dialysis that is associated with an increased risk of death, cardiovascular disease and depression. Fatigue can also impair quality of life (QoL) and the ability to participate in daily activities. Fatigue has been established by patients, caregivers and health professionals as a core outcome for haemodialysis (HD).

OBJECTIVES

We aimed to evaluate the effects of pharmacological and non-pharmacological interventions on fatigue in people with kidney failure receiving dialysis, including HD and peritoneal dialysis (PD), including any setting and frequency of the dialysis treatment.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 18 October 2022 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Studies evaluating pharmacological and non-pharmacological interventions affecting levels of fatigue or fatigue-related outcomes in people receiving dialysis were included. Studies were eligible if fatigue or fatigue-related outcomes were reported as a primary or secondary outcome. Any mode, frequency, prescription, and duration of therapy were considered.

DATA COLLECTION AND ANALYSIS

Three authors independently extracted data and assessed the risk of bias. Treatment estimates were summarised using random effects meta-analysis and expressed as a risk ratio (RR) or mean difference (MD), with a corresponding 95% confidence interval (CI) or standardised MD (SMD) if different scales were used. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Ninety-four studies involving 8191 randomised participants were eligible. Pharmacological and non-pharmacological interventions were compared either to placebo or control, or to another pharmacological or non-pharmacological intervention. In the majority of domains, risks of bias in the included studies were unclear or high. In low certainty evidence, when compared to control, exercise may improve fatigue (4 studies, 217 participants (Iowa Fatigue Scale, Modified Fatigue Impact Scale, Piper Fatigue Scale (PFS), or Haemodialysis-Related Fatigue scale score): SMD -1.18, 95% CI -2.04 to -0.31; I2 = 87%) in HD. In low certainty evidence, when compared to placebo or standard care, aromatherapy may improve fatigue (7 studies, 542 participants (Fatigue Severity Scale (FSS), Rhoten Fatigue Scale (RFS), PFS or Brief Fatigue Inventory score): SMD -1.23, 95% CI -1.96 to -0.50; I2 = 93%) in HD. In low certainty evidence, when compared to no intervention, massage may improve fatigue (7 studies, 657 participants (FSS, RFS, PFS or Visual Analogue Scale (VAS) score): SMD -1.06, 95% CI -1.47, -0.65; I2 = 81%) and increase energy (2 studies, 152 participants (VAS score): MD 4.87, 95% CI 1.69 to 8.06, I2 = 59%) in HD. In low certainty evidence, when compared to placebo or control, acupressure may reduce fatigue (6 studies, 459 participants (PFS score, revised PFS, or Fatigue Index): SMD -0.64, 95% CI -1.03 to -0.25; I2 = 75%) in HD. A wide range of heterogenous interventions and fatigue-related outcomes were reported for exercise, aromatherapy, massage and acupressure, preventing our capability to pool and analyse the data. Due to the paucity of studies, the effects of pharmacological and other non-pharmacological interventions on fatigue or fatigue-related outcomes, including non-physiological neutral amino acid, relaxation with or without music therapy, meditation, exercise with nandrolone, nutritional supplementation, cognitive-behavioural therapy, ESAs, frequent HD sections, home blood pressure monitoring, blood flow rate reduction, serotonin reuptake inhibitor, beta-blockers, anabolic steroids, glucose-enriched dialysate, or light therapy, were very uncertain. The effects of pharmacological and non-pharmacological treatments on death, cardiovascular diseases, vascular access, QoL, depression, anxiety, hypertension or diabetes were sparse. No studies assessed tiredness, exhaustion or asthenia. Adverse events were rarely and inconsistently reported.

AUTHORS' CONCLUSIONS

Exercise, aromatherapy, massage and acupressure may improve fatigue compared to placebo, standard care or no intervention. Pharmacological and other non-pharmacological interventions had uncertain effects on fatigue or fatigue-related outcomes in people receiving dialysis. Future adequately powered, high-quality studies are likely to change the estimated effects of interventions for fatigue and fatigue-related outcomes in people receiving dialysis.

Epidemiology, Pathophysiology, and Clinical Perspectives of Intradialytic Hypertension

BACKGROUND

Individuals with end-stage renal disease on chronic hemodialysis (HD) may encounter numerous HD-associated complications, including intradialytic hypertension (IDHYPER). Although blood pressure (BP) follows a predictable course in the post-HD period, BP levels during the session may vary across the individuals. Typically, a decline in BP is noted during HD, but a significant proportion of patients exhibit a paradoxical elevation.

SUMMARY

Several studies have been conducted to understand the complexity of IDHYPER, but much remains to be elucidated in the future. This review article aimed to present the current evidence regarding the proposed definitions, the pathophysiologic background, the extent and clinical implications of IDHYPER, as well as the possible therapeutic options that have emerged from clinical studies.

KEY MESSAGES

IDHYPER is noted in approximately 15% of individuals undergoing HD. Several definitions have been proposed, with a systolic BP rise >10 mm Hg from pre- to post-dialysis in the hypertensive range in at least four out of six consecutive HD treatments being suggested by the latest Kidney Disease: Improving Global Outcomes. Concerning its pathophysiology, extracellular fluid overload is a crucial determinant, with endothelial dysfunction, sympathetic nervous system overdrive, renin-angiotensin-aldosterone system activation, and electrolyte alterations being important contributors. Although its association with ambulatory BP in the interdialytic period is controversial, IDHYPER is associated with adverse cardiovascular events and mortality. Moving to its management, the antihypertensive drugs of choice should ideally be nondialyzable with proven cardiovascular and mortality benefits. Finally, rigorous clinical and objective assessment of extracellular fluid volume is essential. Volume-overloaded patients should be instructed about the importance of sodium restriction, while physicians ought to alter HD settings toward a greater dry weight reduction. The use of a low-sodium dialysate and isothermic HD could also be considered on a case-by-case basis since no randomized evidence is currently available.

Nephrologists' Perspectives of the Potential Utilization of Home Hemodialysis in Saudi Arabia

Home hemodialysis (HD) is an attractive renal replacement modality that has been shown to provide several benefits to the patient and health-care system. However, home HD programs have not been well-established in Saudi Arabia. We aimed to explore the perspectives of adult nephrology consultants in Saudi Arabia about the potential utilization of home HD via a survey-based cross-sectional study. The survey was distributed via email to all adult nephrology consultants practicing in Saudi Arabia and registered in the Saudi Society of Nephrology and Transplantation. Out of 236 invited consultants, 151 (64%) participated in the study. Half of the participants defined home HD as a trained patient who can independently perform his/her HD sessions at home. Eighty-one (54%) consultants have never managed a patient on home HD during their nephrology training period. More than 70% of participants believed that home HD provides advantages over in-center HD, and that its utilization in Saudi Arabia would be feasible. Although 40% of participants worked in centers with no accredited nephrology training program, most of the remaining participants believed that the local training program did not provide enough teaching about home HD to trainees. Patients' refusal, the nephrologists' lack of motivation and experience, a lack of administrative support, and the lack of infrastructure and nursing support were identified by most participants as the major barriers to the utilization of home HD in Saudi Arabia. Addressing these barriers would be the first step to facilitate initiatives aiming to establish home HD programs in this country.

Cardiovascular Effects of Home Dialysis Therapies: A Scientific Statement From the American Heart Association

Cardiovascular disease is the leading cause of morbidity and mortality in patients with end-stage kidney disease. Currently, thrice-weekly in-center hemodialysis for 3 to 5 hours per session is the most common therapy worldwide for patients with treated kidney failure. Outcomes with thrice-weekly in-center hemodialysis are poor. Emerging evidence supports the overarching hypothesis that a more physiological approach to administering dialysis therapy, including in the home through home hemodialysis or peritoneal dialysis, may lead to improvement in several cardiovascular risk factors and cardiovascular outcomes compared with thrice-weekly in-center hemodialysis. The Advancing American Kidney Health Initiative, which has a goal of increasing the use of home dialysis, is aligned with the American Heart Association's 2024 mission to champion a full and healthy life and health equity. We conclude that incorporation of interdisciplinary care models to increase the use of home dialysis therapies in an equitable manner will contribute to the ultimate goal of improving outcomes for patients with kidney failure and cardiovascular disease.

Experience in Spain with the first patients in home hemodialysis treated with low-flow dialysate monitors

Home hemodialysis (HHD) with low-flow dialysate devices has gained popularity in recent years due to its simple design, portability, and ability to provide greater freedom of movement for our patients. However, there are doubts about the adequacy that this technology offers, since it uses monitors with low-flow bath and lactate. The aim of this study was to demonstrate the clinical benefits of low-flow HHD with the NxStage System One® recently introduced in Spain. We present the results of an observational, retrospective cohort study that included the first patients who started short daily HHD with this device in 12 Spanish centers. We analyzed the evolution of 86 patients at 0, 6 and 12 months, including data related to prescription, and evolution of biochemical parameters related to dialysis dose, anemia, mineral-bone metabolism; evolution of residual renal function, medication usage, and causes of withdrawal during the followup. We were able to demonstrate that this NxStage System One® monitor, in patients with HHD, have provided an adequate dialysis dose, with optimal ultrafiltration rate, with improvement of main biochemical markers of dialysis adequacy. The usage of this technique was associated to a decrease of antihypertensive drugs, phosphate binders and erythropoietin agents, with very good results both patient and technique survival. The simplicity of the technique, together with its good clinical outcomes, should facilitate the growth and utilization of HHD, both in incident and prevalent patients.

From Home Dialysis Access to Home Dialysis Quality

The number and percentage of patients dialyzing at home has steadily increased during the past decade, and federal policy initiatives have driven interest to a new high. However, the mere utilization of home dialysis does not ensure better outcomes for patients and care partners. Although public reporting systems for dialysis quality are mature and robust, the incorporation of home dialysis quality in those systems is immature; the advent of the End-Stage Renal Disease Treatment Choices payment model brings this problem into sharp relief. The home dialysis modalities present both common and unique targets for quality measurement. For both modalities, therapy duration (or its inverse, technique failure) is a potential target. For peritoneal dialysis, peritonitis, catheter complications, and residual kidney function are additional targets; for home hemodialysis, vascular access infections, dialysis adequacy, and treatment adherence are targets. Patient-reported experience measures are also important; this domain is a long-standing disparity, as in-facility hemodialysis patients have been routinely surveyed for several years. The statistical aspect of quality measurement in home dialysis requires some adaptation, as the typical home dialysis program is small, thus presenting a threat to reliability; pooling programs may be necessary. Ultimately, promoting high-quality home dialysis will likely increase utilization of home dialysis.

Toward an individualized determination of dialysis adequacy: a narrative review with special emphasis on incremental hemodialysis

INTRODUCTION

The search for the 'perfect' renal replacement therapy has been paralleled by the search for the perfect biomarkers for assessing dialysis adequacy. Three main families of markers have been assessed: small molecules (prototype: urea); middle molecules (prototype β2-microglobulin); comprehensive and nutritional markers (prototype of the simplified assessment, albumin levels; composite indexes as malnutrition-inflammation score). After an era of standardization of dialysis treatment, personalized dialysis schedules are increasingly proposed, challenging the dogma of thrice-weekly hemodialysis.

AREAS COVERED

In this review, we describe the advantages and limitations of the approaches mentioned above, focusing on the open questions regarding personalized schedules and incremental hemodialysis.

EXPERT OPINION

In the era of personalized dialysis, the assessment of dialysis adequacy should be likewise personalized, due to the limits of 'one size fits all' approaches. We have tried to summarize some of the relevant issues regarding the determination of dialysis adequacy, attempting to adapt them to an elderly, highly comorbidity population, which would probably benefit from tailor-made dialysis prescriptions. While no single biomarker allows precisely tailoring the dialysis dose, we suggest using a combination of clinical and biological markers to prescribe dialysis according to comorbidity, life expectancy, residual kidney function, and small and medium-size molecule depuration.

Experience in Spain with the first patients in home hemodialysis treated with low-flow dialysate monitors

Home hemodialysis (HHD) with low-flow dialysate devices has gained popularity in recent years due to its simple design, portability, and ability to provide greater freedom of movement for our patients. However, there are doubts about the adequacy that this technology offers, since it uses monitors with low-flow bath and lactate. The aim of this study was to demonstrate the clinical benefits of low-flow HHD with the NxStage System One® recently introduced in Spain. We present the results of an observational, retrospective cohort study that included the first patients who started short daily HHD with this device in 12 Spanish centers. We analyzed the evolution of 86 patients at 0, 6 and 12 months, including data related to prescription, and evolution of biochemical parameters related to dialysis dose, anemia, mineral-bone metabolism; evolution of residual renal function, medication usage, and causes of withdrawal during the followup. We were able to demonstrate that this NxStage System One® monitor, in patients with HHD, have provided an adequate dialysis dose, with optimal ultrafiltration rate, with improvement of main biochemical markers of dialysis adequacy. The usage of this technique was associated to a decrease of antihypertensive drugs, phosphate binders and erythropoietin agents, with very good results both patient and technique survival. The simplicity of the technique, together with its good clinical outcomes, should facilitate the growth and utilization of HHD, both in incident and prevalent patients.

Cardiovascular Benefits of Extended-Time Nocturnal Hemodialysis

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

Economic Impact of Home Hemodialysis

Home hemodialysis (HD) is growing in the United States, but the economics of the modality are largely unknown, especially considering the unique aspects of home HD in the United States . In this review, I focus on details of Medicare coverage, which directly applies to most patients on dialysis and influences the policies of private insurers. Key details in Medicare comprise the relationship between home dialysis training and initial Medicare eligibility, reimbursement for home HD training, coverage of additional HD treatments (ie., in excess of 3 treatments per week), and monthly capitated payments to nephrologists. The overarching narrative is that frequent home HD directly increases Medicare costs for outpatient dialysis, but these added costs can be mitigated by lower inpatient expenditures if increased HD treatment frequency lowers the risk of cardiovascular hospitalization and infection control is emphasized. I also review recent international literature; conventional home HD exhibits a superior cost profile, whereas frequent home HD is generally cost-effective over multiple treatment years (ie, if early technique failure is avoided). Out-of-pocket expenses for patients should be considered. The future economics of home HD in the United States will be determined by new equipment, new adaptations of the modality, and new payment models.

Safely reducing haemodialysis frequency during the COVID-19 pandemic

BACKGROUND

Patients undergoing haemodialysis (HD) are at higher risk of developing worse outcomes if they contract COVID-19. In our renal service we reduced HD frequency from thrice to twice-weekly in selected patients with the primary aim of reducing COVID 19 exposure and transmission between HD patients.

METHODS

Dialysis unit nephrologists identified 166 suitable patients (38.4% of our HD population) to temporarily convert to twice-weekly haemodialysis immediately prior to the peak of the COVID-19 pandemic in our area. Changes in pre-dialysis weight, systolic blood pressure (SBP) and biochemistry were recorded weekly throughout the 4-week project. Hyperkalaemic patients (serum potassium > 6.0 mmol/L) were treated with a potassium binder, sodium bicarbonate and received responsive dietary advice.

RESULTS

There were 12 deaths (5 due to COVID-19) in the HD population, 6 of which were in the twice weekly HD group; no deaths were definitively associated with change of dialysis protocol. A further 19 patients were either hospitalised and/or developed COVID-19 and thus transferred back to thrice weekly dialysis as per protocol. 113 (68.1%) were still receiving twice-weekly HD by the end of the 4-week project. Indications for transfer back to thrice weekly were; fluid overload (19), persistent hyperkalaemia (4), patient request (4) and compliance (1). There were statistically significant increases in SBP and pre-dialysis potassium during the project.

CONCLUSIONS

Short term conversion of a large but selected HD population to twice-weekly dialysis sessions was possible and safe. This approach could help mitigate COVID-19 transmission amongst dialysis patients in centres with similar organisational pressures.

Predictive modeling of blood pressure during hemodialysis: a comparison of linear model, random forest, support vector regression, XGBoost, LASSO regression and ensemble method

BACKGROUND

Intradialytic hypotension (IDH) is commonly occurred and links to higher mortality among patients undergoing hemodialysis (HD). Its early prediction and prevention will dramatically improve the quality of life. However, predicting the occurrence of IDH clinically is not simple. The aims of this study are to develop an intelligent system with capability of predicting blood pressure (BP) during HD, and to further compare different machine learning algorithms for next systolic BP (SBP) prediction.

METHODS

This study presented comprehensive comparisons among linear regression model, least absolute shrinkage and selection operator (LASSO), tree-based ensemble machine learning models (random forest [RF] and extreme gradient boosting [XGBoost]), and support vector regression to predict the BP during HD treatment based on 200 and 48 maintenance HD patients containing a total of 7,180 and 2,065 BP records for the training and test dataset, respectively. Ensemble method also was computed to obtain better predictive performance. We compared the developed models based on R², root mean square error (RMSE) and mean absolute error (MAE).

RESULTS

We found that RF (R²=0.95, RMSE=6.64, MAE=4.90) and XGBoost (R²=1.00, RMSE=1.83, MAE=1.29) had comparable predictive performance on the training dataset. However, RF (R²=0.49, RMSE=16.24, MAE=12.14) had more accurate than XGBoost (R²=0.41, RMSE=17.65, MAE=13.47) on testing dataset. Among these models, the ensemble method (R²=0.50, RMSE=16.01, MAE=11.97) had the best performance on testing dataset for next SBP prediction.

CONCLUSIONS

We compared five machine learning and an ensemble method for next SBP prediction. Among all studied algorithms, the RF and the ensemble method have the better predictive performance. The prediction models using ensemble method for intradialytic BP profiling may be able to assist the HD staff or physicians in individualized care and prompt intervention for patients' safety and improve care of HD patients.

Uncertainties in BP management in dialysis patients

Hypertension in dialysis patients is extremely common. In this article, we review the current evidence for blood pressure (BP) goals in hemodialysis patients, and consider the effectiveness of interventions by which BP may be lowered, including manipulation of dietary and dialysate sodium; optimization of extracellular water; prolongation of dialysis time; and antihypertensive medication. Although two meta-analyses suggest lowering BP using antihypertensive drugs might be beneficial in reducing cardiovascular events and mortality, there are insufficient rigorously designed trials in hypertensive hemodialysis populations to determine preferred antihypertensive drug classes. We suggest aiming for predialysis systolic BP between 130 and 159 mm Hg, while at the same time acknowledge the significant limitations of the data upon which it is based. We conclude by summarizing current knowledge as regards management of hypertension in the peritoneal dialysis population and make recommendations for future research in this field.

Blood pressure targets and pharmacotherapy for hypertensive patients on hemodialysis

INTRODUCTION

Hypertension is highly prevalent in patients with end-stage kidney disease on hemodialysis and is often not well controlled. Blood pressure (BP) levels before and after hemodialysis have a U-shaped relationship with cardiovascular and all-cause mortality. Although antihypertensive drugs are recommended for patients in whom BP cannot be controlled appropriately by non-pharmacological interventions, large-scale randomized controlled clinical trials are lacking.

AREAS COVERED

The authors review the pharmacotherapy used in hypertensive patients on dialysis, primarily focusing on reports published since 2000. An electronic search of MEDLINE was conducted using relevant key search terms, including 'hypertension', 'pharmacotherapy', 'dialysis', 'kidney disease', and 'antihypertensive drug'. Systematic and narrative reviews and original investigations were retrieved in our research.

EXPERT OPINION

When a drug is administered to patients on dialysis, the comorbidities and characteristics of each drug, including its dialyzability, should be considered. Pharmacological lowering of BP in hypertensive patients on hemodialysis is associated with improvements in mortality. β-blockers should be considered first-line agents and calcium channel blockers as second-line therapy. Renin-angiotensin-aldosterone system inhibitors have not shown superiority to other antihypertensive drugs for patients on hemodialysis.

Benefits and risks of frequent or longer haemodialysis: weighing the evidence

Although the ability of individuals with end-stage renal disease to maintain body homoeostasis is equally impaired during all weekdays, conventional haemodialysis (HD) treatment is scheduled thrice weekly, containing two short and one long interdialytic interval. This intermittent nature of HD and the consequent fluctuations in volume, metabolic parameters and electrolytes have long been hypothesized to predispose to complications. Large observational studies link the first weekday with an increased risk of cardiovascular morbidity and mortality. Several schemes of frequent and/or longer, home or in-centre HD have been introduced, aiming to alleviate the above risks by both increasing total dialysis duration and reducing the duration of interdialytic intervals. Observational studies in this field have non-uniform results, showing that enhanced frequency in home (but not in-centre) HD is associated with reduced mortality. Evidence from the randomized Daily and Nocturnal Trials of the Frequent HD Network suggest the opposite, showing mortality benefits with in-centre daily but not with home nocturnal dialysis. Secondary analyses of these trials indicate that daily and nocturnal schedules do not have equal effects on intermediate outcomes. Alternative schemes, such as thrice weekly in-centre nocturnal HD or every-other-day HD, seem to also offer improvements in several intermediate endpoints, but need further testing with randomized trials. This review summarizes the effects of frequent and/or longer HD methods on hard and intermediate outcomes, attempting to provide a balanced overview of the field.

The relationship of volume overload and its control to hypertension in hemodialysis patients

Hypertension is highly prevalent and associated with poor clinical outcomes among individuals receiving maintenance hemodialysis (HD). Volume overload is a key modifiable contributor to hypertension and cardiovascular disease in the HD population. Despite their importance, assessment and treatment of volume overload and hypertension remain major clinical challenges and have substantial implications for both clinical outcomes and patient experiences of care. This review will summarize current data on the diagnosis, epidemiology, pathophysiology, and clinical consequences of hypertension and volume overload in HD patients. We will also identify priorities for future research studies.

Low dialysate sodium levels for chronic haemodialysis

BACKGROUND

Cardiovascular (CV) disease is the leading cause of death in dialysis patients, and strongly associated with fluid overload and hypertension. It is plausible that low dialysate [Na+] may decrease total body sodium content, thereby reducing fluid overload and hypertension, and ultimately reducing CV morbidity and mortality.

OBJECTIVES

This review evaluated harms and benefits of using a low (< 138 mM) dialysate [Na+] for maintenance haemodialysis (HD) patients.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 7 August 2018 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs), both parallel and cross-over, of low (< 138 mM) versus neutral (138 to 140 mM) or high (> 140 mM) dialysate [Na+] for maintenance HD patients were included.

DATA COLLECTION AND ANALYSIS

Two investigators independently screened studies for inclusion and extracted data. Statistical analyses were performed using random effects models, and results expressed as risk ratios (RR) for dichotomous outcomes, and mean differences (MD) or standardised MD (SMD) for continuous outcomes, with 95% confidence intervals (CI). Confidence in the evidence was assessed using GRADE.

MAIN RESULTS

We included 12 studies randomising 310 patients, with data available for 266 patients after dropout. All but one study evaluated a fixed concentration of low dialysate [Na+], and one profiled dialysate [Na+]. Three studies were parallel group, and the remaining nine cross-over. Of the latter, only two used a washout between intervention and control periods. Most studies were short-term with a median (interquartile range) follow-up of 3 (3, 8.5) weeks. Two were of a single HD session, and two of a single week's HD. Half of the studies were conducted prior to 2000, and five reported use of obsolete HD practices. Risks of bias in the included studies were often high or unclear, lowering confidence in the results.Compared to neutral or high dialysate [Na+], low dialysate [Na+] had the following effects on "efficacy" endpoints: reduced interdialytic weight gain (10 studies: MD -0.35 kg, 95% CI -0.18 to -0.51; high certainty evidence); probably reduced predialysis mean arterial blood pressure (BP) (4 studies: MD -3.58 mmHg, 95% CI -5.46 to -1.69; moderate certainty evidence); probably reduced postdialysis mean arterial BP (MAP) (4 studies: MD -3.26 mmHg, 95% CI -1.70 to -4.82; moderate certainty evidence); probably reduced predialysis serum [Na+] (7 studies: MD -1.69 mM, 95% CI -2.36 to -1.02; moderate certainty evidence); may have reduced antihypertensive medication (2 studies: SMD -0.67 SD, 95% CI -1.07 to -0.28; low certainty evidence). Compared to neutral or high dialysate [Na+], low dialysate [Na+] had the following effects on "safety" endpoints: probably increased intradialytic hypotension events (9 studies: RR 1.56, 95% 1.17 to 2.07; moderate certainty evidence); probably increased intradialytic cramps (6 studies: RR 1.77, 95% 1.15 to 2.73; moderate certainty evidence).Compared to neutral or high dialysate [Na+], low dialysate [Na+] may make little or no difference to: intradialytic BP (2 studies: MD for systolic BP -3.99 mmHg, 95% CI -17.96 to 9.99; diastolic BP 1.33 mmHg, 95% CI -6.29 to 8.95; low certainty evidence); interdialytic BP (2 studies:, MD for systolic BP 0.17 mmHg, 95% CI -5.42 to 5.08; diastolic BP -2.00 mmHg, 95% CI -4.84 to 0.84; low certainty evidence); dietary salt intake (2 studies: MD -0.21g/d, 95% CI -0.48 to 0.06; low certainty evidence).Due to very low quality of evidence, it is uncertain whether low dialysate [Na+] changed extracellular fluid status, venous tone, arterial vascular resistance, left ventricular mass or volumes, thirst or fatigue. Studies did not examine cardiovascular or all-cause mortality, cardiovascular events, or hospitalisation.

AUTHORS' CONCLUSIONS

It is likely that low dialysate [Na+] reduces intradialytic weight gain and BP, which are effects directionally associated with improved outcomes. However, the intervention probably also increases intradialytic hypotension and reduces serum [Na+], effects that are associated with increased mortality risk. The effect of the intervention on overall patient health and well-being is unknown. Further evidence is needed in the form of longer-term studies in contemporary settings, evaluating end-organ effects in small-scale mechanistic studies using optimal methods, and clinical outcomes in large-scale multicentre RCTs.

Survival and Kidney Transplant Incidence on Home versus In-Center Hemodialysis, following Peritoneal Dialysis Technique Failure

Background

Peritoneal dialysis (PD) technique failure is often accompanied by complications that increase risks of hospitalization and death. Planned transition to hemodialysis may improve outcomes. Transitioning patients from PD to home hemodialysis (HHD) may improve continuity of lifestyle and facilitate delivery of more frequent treatment.

Methods

We analyzed United States Renal Data System (USRDS) data to compare the incidence of death and kidney transplant in patients who transferred from PD to HHD and matched patients who transferred from PD to in-center HD (IHD). We used Fine-Gray regression to estimate hazard ratios (HRs) of death and transplant for HHD versus IHD.

Results

We identified 521 patients who transferred from PD to HHD. Survival in HHD patients was 89.1% at 1 year and 80.5% at 2 years. In intention-to-treat analysis, the HR of death for HHD versus matched IHD patients was 0.76 (95% confidence interval [CI] 0.65 – 0.90). In subsets of non-Medicare and Medicare patients, corresponding HRs were 0.57 (95% CI 0.43 – 0.75) and 0.92 (95% CI 0.75 – 1.13), respectively. Kidney transplant incidence in HHD patients was 10.6% at 1 year and 21.0% at 2 years. In modified intention-to-treat analysis, the HR of transplant for HHD versus matched IHD patients was 1.36 (1.14 – 1.61).

Conclusions

Transfer to HHD after PD technique failure was rare, but associated with lower risk of death and higher incidence of transplant than transfer to IHD. Heterogeneity in relative risks by Medicare coverage suggests uncertainty about the magnitude of benefit. Still, these data suggest that clinical outcomes after PD technique failure can be improved.

No Survival Benefit in Octogenarians and Nonagenarians with Extended Hemodialysis Treatment Time

BACKGROUND

The population of elderly end-stage renal disease patients initiating dialysis is rapidly growing. Although longer treatment is supposed to benefit for hemodialysis (HD) patients through more solute clearance and slower fluid removal, it is not yet clear how treatment session length affects mortality risk in octogenarians and nonagenarians.

METHODS

In a cohort of 112,026 incident HD patients between 2007 and 2011, we examined the association of treatment session length with all-cause mortality, adjusting for demographics and comorbid conditions. We also used restricted spline functions for age to evaluate continuous changes in the association of short (< 210 min) and extended (≥240 min) HD treatment (vs. 210 to < 240 min) with all-cause mortality over continuous age.

RESULTS

During the first 91 days of dialysis, patients aged ≥80 years tended to have the lowest treatment session length (median [interquartile range] 211 [193-230] min, r > 0.5). Longer treatment was associated with better survival in patients < 65 and 65 to < 80 years but not in octogenarians/nonagenarians. The association of extended treatment (≥240 min) with better survival was attenuated across age and not significant among patients aged ≥80 years with a hazard ratio of 1.10 (95% CI 0.99-1.20). Shorter treatment sessions (< 210 min) was associated with higher mortality across all age groups.

CONCLUSION

Extended HD was not associated with lower mortality among octogenarians and nonagenarians, while it was associated with better survival among younger patients. Further studies are needed to determine the optimal treatment session length in elderly incident HD patients.

Hypertension in patients on dialysis: diagnosis, mechanisms, and management

Hypertension (blood pressure > 140/90 mm Hg) is very common in patients undergoing regular dialysis, with a prevalence of 70-80%, and only the minority has adequate blood pressure (BP) control. In contrast to the unclear association of predialytic BP recordings with cardiovascular mortality, prospective studies showed that interdialytic BP, recorded as home BP or by ambulatory blood pressure monitoring in hemodialysis patients, associates more closely with mortality and cardiovascular events. Although BP is measured frequently in the dialysis treatment environment, aspects related to the measurement technique traditionally employed may be unsatisfactory. Several other tools are now available and being used in clinical trials and in clinical practice to evaluate and treat elevated BP in chronic kidney disease (CKD) patients. While we wait for the ongoing review of the CKD Blood Pressure KIDGO guidelines, there is no guideline for the dialysis population addressing this important issue. Thus, the objective of this review is to provide a critical analysis of the information available on the epidemiology, pathogenic mechanisms, and the main pillars involved in the management of blood pressure in stage 5-D CKD, based on current knowledge.

Home hemodialysis treatment and outcomes: retrospective analysis of the Knowledge to Improve Home Dialysis Network in Europe (KIHDNEy) cohort

Background

Utilization of home hemodialysis (HHD) is low in Europe. The Knowledge to Improve Home Dialysis Network in Europe (KIHDNEy) is a multi-center study of HHD patients who have used a transportable hemodialysis machine that employs a low volume of lactate-buffered, ultrapure dialysate per session. In this retrospective cohort analysis, we describe patient factors, HHD prescription factors, and biochemistry and medication use during the first 6 months of HHD and rates of clinical outcomes thereafter.

Methods

Using a standardized digital form, we recorded data from 7 centers in 4 Western European countries. We retained patients who completed ≥6 months of HHD. We summarized patient and HHD prescription factors with descriptive statistics and used mixed modeling to assess trends in biochemistry and medication use. We also estimated long-term rates of kidney transplant and death.

Results

We identified 129 HHD patients; 104 (81%) were followed for ≥6 months. Mean age was 49 years and 66% were male. Over 70% of patients were prescribed 6 sessions per week, and the mean treatment duration was 15.0 h per week. Median HHD training duration was 2.5 weeks. Mean standard Kt/V_urea was nearly 2.7 at months 3 and 6. Pre-dialysis biochemistry was generally stable. Between baseline and month 6, mean serum bicarbonate increased from 23.1 to 24.1 mmol/L (P = 0.01), mean serum albumin increased from 36.8 to 37.8 g/L (P = 0.03), mean serum C-reactive protein increased from 7.3 to 12.4 mg/L (P = 0.05), and mean serum potassium decreased from 4.80 to 4.59 mmol/L (P = 0.01). Regarding medication use, the mean number of antihypertensive medications fell from 1.46 agents per day at HHD initiation to 1.01 agents per day at 6 months (P < 0.001), but phosphate binder use and erythropoiesis-stimulating agent dose were stable. Long-term rates of kidney transplant and death were 15.3 and 5.4 events per 100 patient-years, respectively.

Conclusions

Intensive HHD with low-flow dialysate delivers adequate urea clearance and good biochemical outcomes in Western European patients. Intensive HHD coincided with a large decrease in antihypertensive medication use. With relatively rapid training, HHD should be considered in more patients.

Self-cannulation of the vascular access in home hemodialysis: Overcoming patient-level barriers

Patients with end-stage kidney disease who are considering home hemodialysis (HHD) face the challenge of learning to self-cannulate their arteriovenous access. Current practice discourages the use of tunneled central venous catheters, with recent indications that self-cannulating patients have superior outcomes. Patient-level barriers do not appear to preclude a successful HHD program and should not be viewed as insurmountable by healthcare staff or patients. The healthcare team must address patient fears while instructing the patient to perform self-cannulation safely. Identification and understanding of the barriers perceived by the patient will allow the patient and healthcare team work collaboratively, toward the goal of independence with self-cannulation both during initial training and follow-up care. The aim of this review was to provide a practical resource to aid in the identification and resolution of these patient-level barriers, with the overall goal of improving the patient experience and medical outcomes in home hemodialysis programs.

When is more frequent hemodialysis beneficial?

The use of frequent hemodialysis (HD) is growing, with the hope of improving outcomes in end-stage renal disease. We narratively review the three randomized trials, 15 comparative cohort studies, and several case series of frequent HD that empirically demonstrate the potential efficacy and adverse effects of these regimens. Taken together, the randomized studies suggest frequent HD may result in left ventricular mass regression. This effect is most pronounced when left ventricular mass is abnormal, but attenuated by significant residual urine output. Both frequent short and long HD consistently improved blood pressure control and reduced antihypertensive use, despite greater weekly interdialytic weight gains. Serum phosphate was lowered. Frequent short daytime HD improved health-related quality of life, while frequent long overnight HD did not. Regarding adverse effects, frequent HD patients underwent significantly more procedures to salvage arteriovenous vascular accesses. An absolute increase in hypotensive episodes was observed with frequent short HD, while frequent long HD accelerated residual renal function loss and increased perceived caregiver burden. The effect of frequent HD on mortality is controversial, due to conflicting results and limitations of published studies. Finally, pregnancy outcomes may be substantially better with frequent long HD. On the basis of these data, we suggest frequent HD is most likely to benefit patients with left ventricular hypertrophy particularly if there is minimal urine output, those unable to attain dry weight on a thrice weekly schedule, and pregnant women. All patients receiving frequent HD should be advised of and monitored for potential risks.

Choosing Home Hemodialysis: A Critical Review of Patient Outcomes

BACKGROUND/AIM

Home hemodialysis (HHD) has been associated with improved clinical outcomes vs. in-center HD (ICHD). The prevalence of HHD in the United States is still very low at 1.8%. This critical review compares HHD and ICHD outcomes for survival, hospitalization, cardiovascular (CV), nutrition, and quality of life (QoL).

METHODS

Of 545 publications identified, 44 were not selected after applying exclusion criteria. A systematic review of the identified publications was conducted to compare HHD to ICHD outcomes for survival, hospitalization, CV outcomes, nutrition, and QoL.

RESULTS

Regarding mortality, 10 of 13 trials reported 13-52% reduction; three trials found no differences. According to 6 studies, blood pressure and left ventricular size measurements were generally lower in HHD patients compared to similar measurements in ICHD patients. Regarding nutritional status, conflicting results were reported (8 studies); some found improved muscle mass, total protein, and body mass index in HHD vs. ICHD patients, while others found no significant differences. There were no significant differences in the rate of hospitalization between HHD and ICHD in the 6 articles reviewed. Seven studies on QoL demonstrated positive trends in HHD vs. ICHD populations.

CONCLUSIONS

Despite limitations in the current data, 66% of the publications reviewed (29/44) demonstrated improved clinical outcomes in patients who chose HHD. These include improved survival, CV, nutritional, and QoL parameters. Even though HHD may not be preferred in all patients, a review of the literature suggests that HHD should be provided as a modality choice for substantially more than the current 1.8% of HHD patients in the United States.

Intradialytic hypotension

PURPOSE OF REVIEW

This review focuses on recent advances in our understanding of intradialytic hypotension (IDH) and measures that may reduce its frequency.

RECENT FINDINGS

The frequency and severity of IDH predict the risk for adverse clinical outcomes. The highest mortality risks associated with IDH were observed when the intradialytic systolic blood pressure (SBP) nadirs were <90 and <100 mmHg and the predialysis SBP were ≤159 mmHg or ≥160 mmHg, respectively. Interdialytic weight gain (IDWG) ≥3 kg occurs more frequently among patients with IDH. Prolonged and possibly more frequent dialysis, use of biofeedback devices, dialysate cooling and limiting sodium loading are useful measures to reduce the frequency of IDH.

SUMMARY

Frequent IDH is associated with high IDWGs and a poor prognosis. Studies on prolonged dialysis, biofeedback devices and cooled dialysate have yielded promising results. Intradialytic relative blood volume monitoring devices have been investigated in preventing IDH but results are mixed. Administration of a sodium/hydrogen exchange isoform 3 inhibitor increases stool sodium but has not been shown to decrease IDWG. IDH continues to be a significant dialysis complication deserving of further investigation.

Mortality and Hospitalizations in Intensive Dialysis: A Systematic Review and Meta-Analysis

Background:

Survival and hospitalization are critically important outcomes considered when choosing between intensive hemodialysis (HD), conventional HD, and peritoneal dialysis (PD). However, the comparative effectiveness of these modalities is unclear.

Objective:

We had the following aims: (1) to compare the association of mortality and hospitalization in patients undergoing intensive HD, compared with conventional HD or PD and (2) to appraise the methodological quality of the supporting evidence.

Data Sources:

MEDLINE, Embase, ISI Web of Science, CENTRAL, and nephrology conference abstracts.

Study Eligibility, Participants, and Interventions:

We included cohort studies with comparator arm, and randomized controlled trials (RCTs) with >50% of adult patients (≥18 years) comparing any form of intensive HD (>4 sessions/wk or >5.5 h/session) with any form of chronic dialysis (PD, HD ≤4 sessions/wk or ≤5.5 h/session), that reported at least 1 predefined outcome (mortality or hospitalization).

Methods:

We used the GRADE approach to systematic reviews and quality appraisal. Two reviewers screened citations and full-text articles, and extracted study-level data independently, with discrepancies resolved by consensus. We pooled effect estimates of randomized and observational studies separately using generic inverse variance with random effects models, and used fixed-effects models when only 2 studies were available for pooling. Predefined subgroups for the intensive HD cohorts were classified by nocturnal versus short daily HD and home versus in-center HD.

Results:

Twenty-three studies with a total of 70 506 patients were included. Of the observational studies, compared with PD, intensive HD had a significantly lower mortality risk (hazard ratio [HR]: 0.67; 95% confidence interval [CI]: 0.53-0.84; I² = 91%). Compared with conventional HD, home nocturnal (HR: 0.46; 95% CI: 0.38-0.55; I² = 0%), in-center nocturnal (HR: 0.73; 95% CI: 0.60-0.90; I² = 57%) and home short daily (HR: 0.54; 95% CI: 0.31-0.95; I² = 82%) intensive regimens had lower mortality. Of the 2 RCTs assessing mortality, in-center short daily HD had lower mortality (HR: 0.54; 95% CI: 0.31-0.93), while home nocturnal HD had higher mortality (HR: 3.88; 95% CI: 1.27-11.79) in long-term observational follow-up. Hospitalization days per patient-year (mean difference: –1.98; 95% CI: –2.37 to −1.59; I² = 6%) were lower in nocturnal compared with conventional HD. Quality of evidence was similarly low or very low in RCTs (due to imprecision) and observational studies (due to residual confounding and selection bias).

Limitations:

The overall quality of evidence was low or very low for critical outcomes. Outcomes such as quality of life, transplantation, and vascular access outcomes were not included in our review.

Conclusions:

Intensive HD regimens may be associated with reduced mortality and hospitalization compared with conventional HD or PD. As the quality of supporting evidence is low, patients who place a high value on survival must be adequately advised and counseled of risks and benefits when choosing intensive dialysis. Practice guidelines that promote shared decision-making are likely to be helpful.

BP in Dialysis: Results of a Pilot Study

The optimal BP target for patients receiving hemodialysis is unknown. We randomized 126 hypertensive patients on hemodialysis to a standardized predialysis systolic BP of 110-140 mmHg (intensive arm) or 155-165 mmHg (standard arm). The primary objectives were to assess feasibility and safety and inform the design of a full-scale trial. A secondary objective was to assess changes in left ventricular mass. Median follow-up was 365 days. In the standard arm, the 2-week moving average systolic BP did not change significantly during the intervention period, but in the intensive arm, systolic BP decreased from 160 mmHg at baseline to 143 mmHg at 4.5 months. From months 4-12, the mean separation in systolic BP between arms was 12.9 mmHg. Four deaths occurred in the intensive arm and one death occurred in the standard arm. The incidence rate ratios for the intensive compared with the standard arm (95% confidence intervals) were 1.18 (0.40 to 3.33), 1.61 (0.87 to 2.97), and 3.09 (0.96 to 8.78) for major adverse cardiovascular events, hospitalizations, and vascular access thrombosis, respectively. The intensive and standard arms had similar median changes (95% confidence intervals) in left ventricular mass of -0.84 (-17.1 to 10.0) g and 1.4 (-11.6 to 10.4) g, respectively. Although we identified a possible safety signal, the small size and short duration of the trial prevent definitive conclusions. Considering the high risk for major adverse cardiovascular events in patients receiving hemodialysis, a full-scale trial is needed to assess potential benefits of intensive hypertension control in this population.

A brief review of intradialytic hypotension with a focus on survival

Intradialytic hypotension (IDH), a common complication of ultrafiltration during hemodialysis therapy, is associated with high mortality and morbidity. IDH, defined as a nadir systolic blood pressure of less than 90 mm Hg on more than 30% of treatments, is a relevant definition and is correlated with mortality. Risk factors for IDH include patient demographics, anti-hypertensive medication use, larger interdialytic weight gain, and dialysis prescription features as dialysate sodium, high ultrafiltration rate, and dialysate temperature. A high frequency of IDH events carries a substantial death risk. An ultrafiltration rate >10 mL/h/kg, and even more so >13 mL/h/kg, is highly predictive of cardiovascular and all-cause mortality. Evidence suggests that IDH causes acute reversible segmental myocardial hypoperfusion and contractile dysfunction (myocardial stunning), which can result in long-term loss of myocardial contractility, leading to premature death. IDH also has negative end-organ effects on the brain and gut, contributing to mortality through stroke, and endotoxin translocation with associated inflammation and protein-energy wasting. Given strong association of IDH and dialysis mortality, a paradigm shift to its approach is urgently needed. Randomized controlled trials are required to prospectively test drugs and monitoring devices which may reduce IDH.

Definitions of intradialytic hypotension

Intradialytic hypotension (IDH) is a common and often distressful complication of hemodialysis. However, despite its clinical significance, there is no consensus, evidence-based medical definition for the condition. Over the years, numerous definitions have been implemented in both the clinical and research settings. Definition inconsistencies have hindered data synthesis and the development of evidence-based guidelines for the prevention and treatment of IDH, as well as prevented accurate estimation of the population burden of IDH and patient risk assessment. Most existing IDH definitions are comprised of one or more of the following components: (1) intradialytic BP criteria (requisite BP declines or minimum BP thresholds), (2) the provision of interventions aimed at restoring effective arterial volume, and/or (3) patient-reported symptoms. Remarkably, there are insufficient data to inform IDH definition construction, and it remains unknown if a single, universal definition can adequately capture the condition across patient subgroups, and in clinical and research settings.

Hypertension in dialysis patients: a consensus document by the European Renal and Cardiovascular Medicine (EURECA-m) working group of the European Renal Association - European Dialysis and Transplant Association (ERA-EDTA) and the Hypertension and the Kidney working group of the European Society of Hypertension (ESH)

In patients with end-stage renal disease treated with hemodialysis or peritoneal dialysis, hypertension is very common and often poorly controlled. Blood pressure (BP) recordings obtained before or after hemodialysis display a J-shaped or U-shaped association with cardiovascular events and survival, but this most likely reflects the low accuracy of these measurements and the peculiar hemodynamic setting related with dialysis treatment. Elevated BP by home or ambulatory BP monitoring is clearly associated with shorter survival. Sodium and volume excess is the prominent mechanism of hypertension in dialysis patients, but other pathways, such as arterial stiffness, activation of the renin-angiotensin-aldosterone and sympathetic nervous systems, endothelial dysfunction, sleep apnea and the use of erythropoietin-stimulating agents may also be involved. Nonpharmacologic interventions targeting sodium and volume excess are fundamental for hypertension control in this population. If BP remains elevated after appropriate treatment of sodium-volume excess, the use of antihypertensive agents is necessary. Drug treatment in the dialysis population should take into consideration the patient's comorbidities and specific characteristics of each agent, such as dialysability. This document is an overview of the diagnosis, epidemiology, pathogenesis and treatment of hypertension in patients on dialysis, aiming to offer the renal physician practical recommendations based on current knowledge and expert opinion and to highlight areas for future research.

The nature, consequences, and management of neurological disorders in chronic kidney disease

Perhaps no other organ in the body is affected as often and in as many ways as the brain is in patients with chronic kidney disease (CKD). Several factors contribute to the neurological disorders in CKD including accumulation of uremic toxins, metabolic and hemodynamic disorders, oxidative stress, inflammation, and impaired blood brain barrier among others. The neurological disorders in CKD involve both peripheral and central nervous system. The peripheral neurological symptoms of CKD are due to somatic and cranial peripheral neuropathies as well as a myopathy. The central neurological symptoms of CKD are due to the cortical predominantly cortical, or subcortical lesions. Cognitive decline, encephalopathy, cortical myoclonus, asterixis and epileptic seizures are distinct features of the cortical disorders of CKD. Diffuse white matter disease due to ischemia and hypoxia may be an important cause of subcortical encephalopathy. A special and more benign form of subcortical disorder caused by brain edema in CKD is termed posterior reversible encephalopathy. Subcortical pathology especially when it affects the basal ganglia causes a number of movement disorders including Parkinsonism, chorea and dystonia. A stimulus-sensitive reflex myoclonus is believed to originate from the medullary structures. Sleep disorder and restless leg syndrome are common in CKD and have both central and peripheral origin. This article provides an overview of the available data on the nature, prevalence, pathophysiology, consequences and treatment of neurological complications of CKD.

Frequent hemodialysis: history of the modality and assessment of outcomes

About 660,000 individuals have end-stage renal disease in the USA, the vast majority of whom are receiving standard, in-center, thrice-weekly hemodialysis (HD). The morbidity and mortality among patients receiving standard HD remain unacceptably high. Studies conducted over the past two decades have provided a substantial amount of information on the advantages and drawbacks of providing more frequent HD treatment, either in-center or at home. In this article I summarize these studies, focusing special attention on the randomized, cross-over study assessing outcomes in children who received either frequent, in-center HD or traditional, thrice-weekly, in-center HD performed by Laskin et al. (Pediatr Nephrol doi: 10.1007/s00467-017-3656-x , 2017).

Hypertension in dialysis patients: a consensus document by the European Renal and Cardiovascular Medicine (EURECA-m) working group of the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) and the Hypertension and the Kidney working group of the European Society of Hypertension (ESH)

In patients with end-stage renal disease (ESRD) treated with haemodialysis or peritoneal dialysis, hypertension is common and often poorly controlled. Blood pressure (BP) recordings obtained before or after haemodialysis display a J- or U-shaped association with cardiovascular events and survival, but this most likely reflects the low accuracy of these measurements and the peculiar haemodynamic setting related to dialysis treatment. Elevated BP detected by home or ambulatory BP monitoring is clearly associated with shorter survival. Sodium and volume excess is the prominent mechanism of hypertension in dialysis patients, but other pathways, such as arterial stiffness, activation of the renin-angiotensin-aldosterone and sympathetic nervous systems, endothelial dysfunction, sleep apnoea and the use of erythropoietin-stimulating agents may also be involved. Non-pharmacologic interventions targeting sodium and volume excess are fundamental for hypertension control in this population. If BP remains elevated after appropriate treatment of sodium and volume excess, the use of antihypertensive agents is necessary. Drug treatment in the dialysis population should take into consideration the patient's comorbidities and specific characteristics of each agent, such as dialysability. This document is an overview of the diagnosis, epidemiology, pathogenesis and treatment of hypertension in patients on dialysis, aiming to offer the renal physician practical recommendations based on current knowledge and expert opinion and to highlight areas for future research.

Interplay of volume, blood pressure, organ ischemia, residual renal function, and diet: certainties and uncertainties with dialytic management

Extracellular fluid volume overload and its inevitable consequence, hypertension, increases cardiovascular mortality in the long term by leading to left ventricular hypertrophy, heart failure, and ischemic heart disease in dialysis patients. Unlike antihypertensive medications, a strict volume control strategy provides optimal blood pressure control without need for antihypertensive drugs. However, utilization of this strategy has remained limited because of several factors, including the absence of a gold standard method to assess volume status, difficulties in reducing extracellular fluid volume, and safety concerns associated with reduction of extracellular volume. These include intradialytic hypotension; ischemia of heart, brain, and gut; loss of residual renal function; and vascular access thrombosis. Comprehensibly, physicians are hesitant to follow strict volume control policy because of these safety concerns. Current data, however, suggest that a high ultrafiltration rate rather than the reduction in excess volume is related to these complications. Restriction of dietary salt intake, increased frequency, and/or duration of hemodialysis sessions or addition of temporary extra sessions during the process of gradually reducing postdialysis body weight in conventional hemodialysis and discontinuation of antihypertensive medications may prevent these complications. We believe that even if an unwanted effect occurs while gradually reaching euvolemia, this is likely to be counterbalanced by favorable cardiovascular outcomes such as regression of left ventricular hypertrophy, prevention of heart failure, and, ultimately, cardiovascular mortality as a result of the eventual achievement of normal extracellular fluid volume and blood pressure over the long term.

Effect of Nocturnal Hemodialysis versus Conventional Hemodialysis on End-Stage Renal Disease: A Meta-Analysis and Systematic Review

Objectives

The purpose of this study is to assess the efficacy and safety of nocturnal hemodialysis on end-stage renal disease (ESRD) patients.

Methods

We searched Medline, EmBase, and the Cochrance Central Register of Controlled Trials for studies up to January 2016. Analysis was done to compare variant outcomes of different hemodialysis schedules, including mortality, cardiovascular-associated variables, uremia-associated variables, quality of life (QOL), side-effects, and drug usage.

Results

We collected and analyzed the results of 28 studies involving 22,508 patients in our meta-analysis. The mortality results in this meta-analysis indicated that the nocturnal hemodialysis (NHD) group was not significantly different from conventional hemodialysis (CHD) group (Mortality: OR: 0.75; 95% confidence intervals (CIs): 0.52 to 1.10; p = 0.145), but the CHD group had significantly fewer number of hospitalizations than the NHD group (OR: 1.54; 95%CI: 1.32 to 1.79; p<0.001). NHD was superior to CHD for cardiovascular-associated (left ventricular hypertrophy [LVH]: SMD: -0.39; 95%CI: -0.68 to -0.10; p = 0.009, left ventricular hypertrophy index [LVHI]: SMD: -0.64; 95%CI: -0.83 to -0.46; p<0.001) and uremia-associated intervention results (Serum albumin: SMD: 0.89; 95%CI: 0.41 to 1.36; p<0.001). For the assessment of quality of life, NHD treatment significantly improved the patients’ QOL only for SF36-Physical Components Summary (SMD: 0.43; 95%CI: 0.26 to 0.60; p<0.001). NHD intervention was relatively better than CHD for anti-hypertensive drug usage (SMD: -0.48; 95%CI: -0.91 to -0.05; p = 0.005), and there was no difference between groups in our side-effects assessment.

Conclusion

NHD and CHD performed similarly in terms of ESRD patients’ mortality and side-effects. NHD was superior to CHD for cardiovascular-associated and uremia-associated results, QOL, and drug usage; for number of hospitalizations, CHD was relatively better than NHD.

Hemodialysis Treatment Time: As Important as it Seems?

Hemodialysis treatment time and Kt/V can both be considered to be primary measures of hemodialysis adequacy, because when either goes to zero, mortality is certain in patients without residual kidney function. Treatment time is important, but it needs to be adjusted based on surface-area-normalized Kt/V, residual kidney function, and expected ultrafiltration rate. Rescaling dose of dialysis measured as Kt/V to body surface area prevents ultrashort dialysis in small patients, women, and children with minimal residual kidney function. Most if not all of the observational studies of associations between outcome and dialysis session length are probably confounded by dose targeting bias. Once adequate Kt/V (taking into account body surface area) has been provided, adequate dialysis time probably is most relevant in terms of limiting the need for a high fluid removal rate. The latter may adversely impact survival by causing recurrent ischemia to cardiovascular and other tissues. There is little high-quality evidence at this time to support a minimum 4-hour treatment time for all patients, regardless of body size, solute removal, or residual kidney function. On the other hand, there is little evidence that prolonging weekly treatment time up to 24 hours per week is harmful. The final decision regarding treatment time is best individualized, based on patient acceptability and experience, residual kidney function, body surface-area-normalized Kt/V, and expected ultrafiltration rate.

Extracellular Volume Overload and Increased Vasoconstriction in Patients With Recurrent Intradialytic Hypertension

Background/Aims

Intradialytic hypertension (IH) occurs frequently in some hemodialysis patients and increases mortality risk. We simultaneously compared pre-dialysis, post-dialysis and changes in extracellular volume and hemodynamics in recurrent IH patients and controls.

Methods

We performed a case-control study among prevalent hemodialysis patients with recurrent IH and hypertensive hemodialysis controls. We used bioimpedance spectroscopy and impedance cardiography to compare pre-dialysis, post-dialysis, and intradialytic change in total body water (TBW) and extracellular water (ECW), as well as cardiac index (CI) and total peripheral resistance index (TPRI).

Results

The ECW/TBW was 0.453 (0.05) pre-dialysis and 0.427 (0.04) post-dialysis in controls vs. 0.478 (0.03) and 0.461 (0.03) in IH patients (p=0.01 post-dialysis). The ECW/TBW change was −0.027 (0.03) in controls and −0.013 (0.02) in IH patients (p=0.1). In controls, pre- and post-dialysis TPRI were 3254 (994) and 2469 (529) dynes/sec/cm²/m² vs. 2983 (747) and 3408 (980) dynes/sec/cm²/m² in IH patients (p=0.002 post-dialysis). There were between-group differences in TPRI change (0=0.0001), but not CI (p=0.09).

Conclusions

Recurrent intradialytic hypertension is associated with higher post-dialysis extracellular volume and TPRI. Intradialytic TPRI surges account for the vasoconstrictive state post-dialysis, but intradialytic fluid shifts may contribute to post-hemodialysis volume expansion.