Effects of thrice weekly nocturnal hemodialysis on arterial stiffness

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.

[Prolonged hemodialysis: Rationale, practical organization, results]

In France, long nocturnal dialyses, eight hours three-times a week, are sparsely proposed. However, numerous studies reported that this specific type of dialysis is associated to better blood pressure control, better cardiac remodeling, better mineral and nutritional balance as well as better life quality and survival rate. MATERIAL AND METHODS: In this study, we aimed at quantifying the benefits, risks and obstacles of developing night dialysis and at describing the results of a program that took place in Rennes from 2002 to 2019. Data were collected between 2008 and 2014 for eighteen case-patients and were compared to thirty-six controls that underwent conventional dialysis. Patients were paired according sex, age and year of dialysis start. RESULTS: The median age for dialysis start was 47.5 years [27-60] with a male prevalence (5/1). After six months, a significant difference was reported for postdialytic, systolic and diastolic pressure (respectively 126±15 vs 139±21 [P=0.04] and 72±9 vs 81±14 [P=0.02]) despite an antihypertensive reduction ranging from 2.4±1.4 to 1.3±0.9 per day at six months and 0.7±0.9 at one year (P=0.02). An increase of nPCR was evidenced at 6 and 9 months (P=0.02). At the end of the study, the phosphate level was maintained for both cohorts at the expense of an increased consumption of phosphate binder for the long nocturnal dialysis group (P=0.025). As a whole, 61% of the patients that pursued long night dialysis maintained a professional activity compared to only 30% for the controls (P=0.04). This highlights the advantages of night dialysis for maintaining employment but also the bias that represents the employment status in observational study on this specific topic.

Nocturnal haemodialysis is associated with a reduced occurrence of low triiodothyronine serum levels in haemodialysed patients

Background

End-stage renal disease (ESRD) is associated with a broad spectrum of morphological and functional thyroid disorders. Recent studies have shown that low free triiodothyronine (fT3) levels are related to inflammatory status and endothelial activation in ESRD patients on haemodialysis (HD). Limited data exist about a possible relationship between dialysis regimen, namely long nocturnal haemodialysis (LNHD), and thyroid function parameters. The aim of this study was to evaluate the relationship between dialysis regimen and thyroid function, and consequently with the main patient outcomes.

Methods

To this purpose, we performed a retrospective, single-centre cohort study including 220 incident chronic HD patients treated during an 8-year period (from January 2010 to December 2017). The main clinical and haematochemical parameters, including thyroid function, were evaluated and related to the main patient outcomes.

Results

Patients with low fT3 levels (<3.05 ng/mL) showed significantly lower survival rates than patients with normal fT3 levels (>3.05 ng/mL) (P < 0.001), although there were no substantial differences in the demographic and clinical characteristics between the two groups. After propensity score 1:3 matching of 25 patients treated with nocturnal HD to 75 patients treated with diurnal HD, LNHD patients showed significantly higher survival rates (88.0% versus 61.3%, P = 0.001) and lower incidence of cardiovascular events than patients on diurnal dialysis (8.0% versus 40.0%, P = 0.001). Moreover, an 8-year time-dependent analysis showed that at any time, except for baseline, the rate of patients with fT3 levels >3.05 ng/mL was significantly higher in LNHD patients than in patients treated with diurnal dialysis.

Conclusions

Our data suggest that the application of alternative dialysis regimens, also reducing the frequency of low T3, could ameliorate outcomes and therefore reduce the incidence of cardiovascular events in HD patients.

Arterial stiffness: hemodialysis versus hemodiafiltration

Background and aims

Arterial stiffness seems to be influenced by the dialysis method, but studies are sparse and the results discordant. High substitution volume online hemodiafiltration appears to have beneficial cardiovascular effects in dialysis patients, but its effects on arterial stiffness are not investigated. We aimed to analyze arterial stiffness parameters in high substitution volume post-dilution online hemodiafiltration and compare results to high-flux hemodialysis.

Methods

We studied arterial stiffness parameters using the oscillometric method (Arteriograph IrDA, TensioMed, Budapest, Hungary) in 23 non-diabetic patients on high substitution volume online postdilution hemodiafiltration and 23 non-diabetic patients on high-flux hemodialysis. Dialysis vintage was at least 6 months in all subjects.

Results

Hemodiafiltration-treated patients showed a more favorable arterial stiffness profile. Pulse wave velocity was significantly higher in hemodialysis compared to hemodiafiltration patients (10.39±2.29 m/s vs 9.0±1.7 m/s, p=0.026). Augmentation indexes and the diastolic reflection area were also significantly elevated hemodialysis patients compared to hemodiafiltration patients.

Conclusions

High substitution volume online postdilution hemodiafiltration could have a beneficial effect on arterial stiffness and should be assessed in properly sized controlled trials.

In-Center Nocturnal Hemodialysis Versus Conventional Hemodialysis: A Systematic Review of the Evidence

BACKGROUND

Owing to its longer treatment duration-up to 8 hours per dialysis treatment-in-center thrice-weekly nocturnal hemodialysis (HD) is receiving greater attention. To better understand the evidence for in-center nocturnal HD, we sought to systematically review the literature to determine the effects of in-center nocturnal HD versus conventional HD on clinically relevant outcomes.

STUDY DESIGN

We searched MEDLINE, Embase, Evidence-Based Medicine Reviews (EBMR), Web of Science, and Scopus from the earliest date in the database to November 2016.

SETTING & POPULATION

Adults receiving in-center nocturnal HD compared with those receiving conventional HD.

SELECTION CRITERIA FOR STUDIES

All quasi-experimental and observational studies were considered; randomized trials were sought but not found.

PREDICTOR

Nocturnal vs conventional in-center HD.

OUTCOMES

Indexes of blood pressure and left ventricular hypertrophy, markers of anemia, measures of bone mineral metabolism, nutrition, quality of life, sleep quality, episodes of intradialytic hypotension, hospitalization, and mortality.

RESULTS

Of 2,086 identified citations, 21 met the inclusion criteria, comprising a total of 1,165 in-center nocturnal HD patients and 15,865 conventional HD patients. Although there was substantial heterogeneity in reporting of outcomes, we pooled data for measures of blood pressure, anemia, and mineral metabolism. Though heterogeneity was generally high, in-center nocturnal HD was associated with improved systolic blood pressure (-3.18 [95% CI, -5.58 to -0.78) mm Hg, increased hemoglobin levels (0.53 [95% CI, 0.11-0.94] g/dL), and lower serum phosphate levels (-0.97 [95% CI, -1.48 to -0.46] mg/dL).

LIMITATIONS

No randomized trials have been conducted to address the clinical effects of in-center nocturnal HD. The quality of the observational literature contributing to the results of this review was generally poor to moderate. Confounded outcomes are a significant concern. Publication bias and outcome reporting bias remain possibilities.

CONCLUSIONS

Relative to conventional HD, in-center nocturnal HD was associated with improvements in several clinically relevant outcomes. Other benefits may not have been detected due to small sample sizes of included studies; no prespecified outcome was worse with in-center nocturnal HD.

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.

Reduction of carbamylated albumin by extended hemodialysis

Introduction Among conventional hemodialysis (CHD) patients, carbamylated serum albumin (C-Alb) correlates with urea and amino acid deficiencies and is associated with mortality. We postulated that reduction of C-Alb by intensive HD may correlate with improvements in protein metabolism and cardiac function. Methods One-year observational study of in-center nocturnal extended hemodialysis (EHD) patients and CHD control subjects. Thirty-three patients receiving 4-hour CHD who converted to 8-hour EHD were enrolled, along with 20 controls on CHD. Serum C-Alb, biochemistries, and cardiac MRI parameters were measured before and after 12 months of EHD. Findings EHD was associated with reduction of C-Alb (average EHD change -3.20 mmol/mol [95% CI -4.23, -2.17] compared to +0.21 [95% CI -1.11, 1.54] change in CHD controls, P < 0.001). EHD was also associated with increases in average essential amino acids (in standardized units) compared to CHD (+0.38 [0.08, 0.68 95%CI]) vs. -0.12 [-0.50, 0.27, 95% CI], P = 0.047). Subjects who reduced C-Alb more than 25% were found to have reduced left ventricular mass, increased urea reduction ratio, and increased serum albumin compared to nonresponders, and % change in C-Alb significantly correlated with % change in left ventricular mass. Discussion EHD was associated with reduction of C-Alb as compared to CHD, and reduction of C-Alb by EHD correlates with reduction of urea. Additional studies are needed to test whether reduction of C-Alb by EHD also correlates with improved clinical outcomes.

The effects of single hemodialysis session on arterial stiffness in hemodialysis patients

Increased arterial stiffness in hemodialysis patients is a strong predictor of cardiovascular morbidity and mortality. Pulse wave velocity (PWV) and augmentation index (AIx), which are markers of arterial stiffness, were used to determine the severity of vascular damage noninvasively. This study aimed to investigate the effects of solute volume removal and hemodynamic changes on PWV and AIx of a single hemodialysis session. Thirty hemodialysis patients were enrolled in the study. Before initiation of hemodialysis, every 15 minutes during hemodialysis, and 30 minutes after the completion of the session, measurements of PWV and AIx@75 (normalized with heart rate 75 bpm) were obtained from each patient. Body composition was analyzed by bioimpedance spectroscopy device before and 30 minutes after completion of the hemodialysis session. During the hemodialysis, no significant change was observed in AIx@75. However, PWV decreased steadily during the session reaching statistically significant level at 135th minute (P = 0.026), with a maximal drop at 210th minute (P < 0.001). At 210th minute, decrease in PWV correlated positively with the decrease in central systolic blood pressure, central diastolic blood pressure, central pulse pressure, augmentation pressure, and AIx@75. Multiple regression analysis showed that decrease in PWV at 210th minute was associated with decrease in central systolic blood pressure and central pulse pressure. Ultrafiltration during hemodialysis had no significant effect on PWV and AIx@75. Delta urea correlated positively with delta PWV at 240th minute. A significant decrease in PWV was observed during hemodialysis and correlated with urea reduction; however, we were unable to document any effect of volume removal on arterial stiffness.

In-center nocturnal hemodialysis

Dialysis intensification from conventional regimens (typically thrice weekly, 4 hours per session) is increasingly utilized with the intent of improving the cardiovascular health and quality of life of chronic dialysis recipients. While home nocturnal hemodialysis offers the opportunity for maximal intensification of dialysis, it is inaccessible to the majority of dialysis recipients who are unable to self-administer hemodialysis in their own homes. In-center nocturnal hemodialysis (INHD) permits the intensification of conventional hemodialysis with the benefits of nursing support and supervision in addition to freedom from dialysis during productive daytime hours. Although no randomized trials have evaluated the relative merits of INHD, preliminary data indicate that INHD is a viable option that may confer a variety of benefits for chronic dialysis recipients.

Cost analysis of in-centre nocturnal compared with conventional hemodialysis

Background

Provision of in-centre nocturnal hemodialysis (ICNHD; 6–8 hours thrice weekly) is associated with health benefits, but the economic implications of providing this treatment are unclear.

Objective

We conducted a health care costing study comparing ICNHD to in-centre thrice-weekly conventional hemodialysis (CvHD).

Design

Micro-costing of both ICNHD and CvHD as practiced at our centre.

Setting

Hemodialysis unit at a tertiary-care hospital in Edmonton.

Participants

An informal survey of 2 other Canadian ICNHD programs was conducted to inform practices that may deviate from ours to guide sensitivity analysis.

Measurements

Resources consumed for each strategy were determined, and the cost of each unit (CAN $2012) was used to calculate incremental costs of ICNHD and CvHD.

Methods

We focused on resources that differ between strategies (staffing, dialysis materials, and utilities). The reference case considered 1:3 staff to patient ratio; alternate scenarios explored nursing pay grade and ratio, full care vs. self-care dialysis (including training costs), and medication costs.

Results

In the reference case, ICNHD was $61 more costly per dialysis treatment compared with CvHD ($9,538 per patient per year). Incremental annual costs for staffing, dialysis materials, and utilities were $8,201, $1,193, and $144, respectively. If ICNHD reduces medication use (anti-hypertensives, bone mineral metabolism medications), the incremental cost of ICNHD decreases to $8,620 per patient per year. In a scenario of self-care ICNHD utilizing a staff-to-patient ratio of 1:10, ICNHD is more costly in year 1 ($15,196), but results in cost savings of $2,625 in subsequent years compared with CvHD.

Limitations

The findings of this cost analysis may not be generalizable to other health care systems, including other parts of Canada.

Conclusions

Compared to CvHD, provision of ICNHD is more expensive, largely driven by increased staffing costs as patients dialyze longer. Alternate staffing models, including self-care ICNHD with minimal staff, may lead to net cost savings. The incremental cost of treatment should be considered in the context of impact on patient health outcomes, staffing model, and pragmatic factors, such as current capacity for daytime CvHD and the capital costs of new dialysis stations.

Electronic supplementary material

The online version of this article (doi:10.1186/2054-3581-1-14) contains supplementary material, which is available to authorized users.