Rapid fluid removal during dialysis is associated with cardiovascular morbidity and mortality

Correlation between ultrafiltration rate and hemoglobin level and erythropoietin response in hemodialysis patients

This study aimed to investigate the correlation between ultrafiltration rate (UFR) and hemoglobin levels and erythropoietin (EPO) response in patients receiving maintenance hemodialysis (MHD). 225 MHD patients were divided into three groups according to the UFR: < 10 ml/h/kg, 10-13 ml/h/kg, and >13 ml/h/kg. Clinical parameters and prognosis were compared among the groups. Multiple linear correlation and regression analyses were conducted. SPSS 26.0 (IBM, Chicago, IL, USA) was used to analyze all statistics. The UFR < 10 ml/h/kg group was older than the other groups (p < 0.05). The UFR > 13 ml/h/kg group had the highest SpKt/V (p < 0.05), monthly EPO dose/weight (p < 0.001), and EPO resistance index (p < 0.001), as well as the lowest dry weight (p < 0.001), BMI (p < 0.001), hemoglobin (p < 0.001), hematocrit (p < 0.05), and red blood cell count (p < 0.05). Multiple linear regression analysis showed that sex, dry weight, UFR, calcium, phosphorus, albumin, and C-reactive protein levels were associated with hemoglobin levels. Multivariate logistic regression analysis revealed that a higher UFR was associated with lower hemoglobin levels, while male sex and higher levels of calcium and albumin were associated with higher hemoglobin levels. High UFR is associated with more severe anemia and EPO resistance in MHD. This study provides new insights into anemia management in patients undergoing hemodialysis.

Changes in right ventricular dimensions, function, and pulmonary circulation loading according to the degree of interdialytic weight gain in maintenance hemodialysis patients

INTRODUCTION

The aim of this study was to investigate changes in echocardiographic right ventricular (RV) indices in relation to the degree of fluid accumulation between hemodialysis sessions, evaluated according to the recommended threshold of interdialytic-weight-gain corrected for dry weight (IDWG%).

METHODS

A post-hoc analysis was performed using data from 41 maintenance hemodialysis patients. Patients were divided into a higher (>4.5%) and a lower (<4.5%) IDWG% group and underwent an echocardiographic assessment at the start and the end of the 3-day and the 2-day interdialytic interval.

RESULTS

RV systolic pressure (RVSP) increments were more pronounced in the higher compared to the lower IDWG% group (16.43 ± 5.37 vs. 14.11 ± 13.38 mm Hg respectively, p = 0.015) over the 3-day interval, while changes in RV filling pressures, did not differ significantly between the groups (p = 0.84).

CONCLUSIONS

During the 3-day interdialytic interval, pulmonary circulation is particularly overloaded in patients with fluid accumulation higher than the recommended thresholds, as evidenced by higher RVSP elevations.

Personalized prediction of intradialytic hypotension in clinical practice: Development and evaluation of a novel AI dashboard incorporating risk factors from previous and current dialysis sessions

BACKGROUND

Intradialytic hypotension (IDH) is one of the most common and critical complications of hemodialysis. Despite many proven factors associated with IDH, accurately predicting it before it occurs for individual patients during dialysis sessions remains a challenge.

PURPOSE

To establish artificial intelligence (AI) predictive models for IDH, which consider risk factors from previous and ongoing dialysis to optimize model performance. We then implement a novel digital dashboard with the best model for continuous monitoring of patients' status undergoing hemodialysis. The AI dashboard can display the real-time probability of IDH for each patient in the hemodialysis center providing an objective reference for care members for monitoring IDH and treating it in advance.

METHODS

Eight machine learning (ML) algorithms, including Logistic Regression (LR), Random Forest (RF), Support Vector Machine (SVM), K Nearest Neighbor (KNN), Light Gradient Boosting Machine (LightGBM), Multilayer Perception (MLP), eXtreme Gradient Boosting (XGBoost), and NaiveBayes, were used to establish the predictive model of IDH to determine if the patient will acquire IDH within 60 min. In addition to real-time features, we incorporated several features sourced from previous dialysis sessions to improve the model's performance. The electronic medical records of patients who had undergone hemodialysis at Chi Mei Medical Center between September 1, 2020 and December 31, 2020 were included in this research. Impact evaluation of AI assistance was conducted by IDH rate.

RESULTS

The results showed that the XGBoost model had the best performance (accuracy: 0.858, sensitivity: 0.858, specificity: 0.858, area under the curve: 0.936) and was chosen for AI dashboard implementation. The care members were delighted with the dashboard providing real-time scientific probabilities for IDH risk and historic predictive records in a graphic style. Other valuable functions were appended in the dashboard as well. Impact evaluation indicated a significant decrease in IDH rate after the application of AI assistance.

CONCLUSION

This AI dashboard provides high-quality results in IDH risk prediction during hemodialysis. High-risk patients for IDH will be recognized 60 min earlier, promoting individualized preventive interventions as part of the treatment plan. Our approachis believed to promise an excellent way for IDH management.

Endothelin-1, Extracellular Volume Overload, and Hemodynamics in Hemodialysis Patients

BACKGROUND

Extracellular volume (ECV) overload and endothelial cell dysfunction are mortality risk factors in hemodialysis (HD) patients. Endothelin-1 (ET-1), an endothelium-derived vasoconstrictive peptide, is associated with poor outcomes in HD patients. We hypothesized there would be associations between ET-1 and ECV overload in hypertensive HD patients.

METHODS

We obtained pre-HD ET-1, ECV/weight (bioimpedance spectroscopy), pre-HD hemodynamics, and ambulatory blood pressure (BP) in an HD cohort. Following appropriate transformations, we conducted correlation and linear regression analyses idendifying associations between ET-1, ECV overload, total peripheral resistance index (TPRI), cardiac index (CI), and ambulatory BP.

RESULTS

Among 66 patients, median ET-1 was 1.93 (1.49-2.56) pg/ml. Median pre-HD ECV/weight, median TPRI, mean CI, and mean systolic ambulatory BP were 0.25 (0.22-0.30) l/kg, 3,161 (2,711-3,642) dynes × s/cm-5/m2, 2.92 (0.6) l/min/m2, and 143 (14) mm Hg, respectively. After reciprocal-transformation, ET-1 correlated with reciprocal-transformed ECV/weight (r = 0.3, P = 0.01), log-transformed TPRI (r = -0.3, P = 0.006), CI (r = 0.3, P = 0.009), and ambulatory BP (r = -0.3, P = 0.02). These associations persisted in linear regression analysis (β = 0.15, P = 0.002; β = -0.8, P = 0.002; β = 0.2, P = 0.002; β = -19, P = 0.03).

CONCLUSIONS

In hypertensive HD patients, ET-1 associates with ECV overload higher TPRI and ambulatory BP, and lower CI. Further research is necessary to determine if ECV reduction lowers ET-1 or if pharmacologic ET-1 antagonism can improve outcomes in HD patients with refractory ECV overload.

Effect of Pre- and Post-Dialysis Exercise on Functional Capacity Using Portable Ergometer in Chronic Kidney Disease Patients

OBJECTIVE

To assess whether performing exercises during hemodialysis reduces the risk of developing intradialytic hypotension and enhances exercise capacity in patients with chronic kidney disease.

METHODS

This study included patients aged ≥18 years undergoing hemodialysis. Participants performed exercises using a portable lower extremity ergometer during hemodialysis sessions for 3 weeks. Data regarding walking distance, knee strength, quality of life, fat-free mass, arterial pressure, blood pressure, heart rate, frequency of intradialytic hypotension, fatigue, and duration of hemodialysis were collected and analyzed.

RESULTS

Significant improvements in walking distance and knee strength were observed following the implementation of exercise training during hemodialysis. Although there was no significant reduction in the frequency of intradialytic hypotension, a decreasing trend was noted. Other parameters such as quality of life and fatigue did not show significant changes.

CONCLUSION

Using a portable ergometer during hemodialysis improved exercise capacity and knee strength in patients with chronic kidney disease. There was a trend toward reduced intradialytic hypotension, suggesting potential cardiovascular benefits. Further research with larger sample sizes is needed to confirm these findings.

Adequacy of Dialysis and Incidence of Atrial Fibrillation in Patients Undergoing Hemodialysis

BACKGROUND

Atrial fibrillation (AF) can lead to stroke, heart failure, and mortality and has a greater prevalence in dialysis patients than in the general population. Several studies have suggested that uremic toxins may contribute to the development of AF. However, the association between dialysis adequacy and incident AF has not been well established.

METHODS

In this retrospective nationwide cohort study, we analyzed data from the Korean National Periodic Hemodialysis Quality Assessment from 2013 to 2015 of patients who received outpatient maintenance hemodialysis 3× a week. The main exposure was single pooled Kt/V (spKt/V), which is the dialysis adequacy index, and the primary outcome was the development of AF. For the primary analysis, patients were categorized into quartiles according to baseline spKt/V. The lowest quartile, representing the lowest adequacy, was used as the reference group. Fine-Gray subdistribution hazard models were used, treating all-cause mortality as a competing risk.

RESULTS

Of 25 173 patients, the mean age was 60 (51-69) years, and 14 772 (58.7%) were men. During a median follow-up of 5.7 years, incident AF occurred in a total of 3883 (15.4%) patients. Participants with a higher spKt/V tended to have lower AF incidence. In survival analysis, a graded association was observed between the risk of incident AF and spKt/V quartiles: subdistribution hazard ratios and 95% CIs for the second, third, and the highest quartile compared with the lowest quartile were 0.90 (95% CI, 0.82-0.98), 0.84 (95% CI, 0.77-0.93), and 0.79 (95% CI, 0.72-0.88), respectively.

CONCLUSIONS

This nationwide cohort study showed that a higher spKt/V is associated with a reduced risk of incident AF. These findings suggests that reducing uremic toxin burden through enhanced dialysis clearance may be associated with a lower risk of AF development in patients undergoing maintenance hemodialysis.

Twice Weekly versus Thrice Weekly Hemodialysis-A Pilot Cross-Over Equivalence Trial

Key Points

Background

The 2015 Update of the Kidney Disease Outcomes Quality Initiative (KDOQI) Guideline for Hemodialysis Adequacy increased the contribution of residual kidney function in calculating standard Kt/Vurea (stdKt/Vurea). However, no study has assessed the effect of prescribing twice weekly hemodialysis according to this guideline on patients' quality of life or uremic solute levels.

Methods

Twenty six hemodialysis patients with average residual urea clearance (Kru) 4.7±1.8 ml/min and hemodialysis vintage of 12±15 months (range 2 months to 4.9 years) underwent a cross-over trial comparing four weeks of twice weekly hemodialysis and four weeks of thrice weekly hemodialysis. Twice weekly hemodialysis was prescribed to achieve stdKt/Vurea 2.2 incorporating Kru using the 2015 KDOQI Guideline. Thrice weekly hemodialysis was prescribed to achieve spKt/Vurea 1.3 regardless of Kru. Quality of life and plasma levels of secreted uremic solutes and β 2 microglobulin were assessed at the end of each period.

Results

Equivalence testing between twice and thrice weekly hemodialysis based on the Kidney Disease Quality of Life instrument (primary analysis) was inconclusive. Symptoms as assessed by the secondary outcomes Dialysis Symptom Index and Post-Dialysis Recovery Time were not worse with twice weekly hemodialysis. StdKt/Vurea was adequate during twice weekly hemodialysis (2.7±0.5), and ultrafiltration rate and plasma potassium were controlled with minimally longer treatment times (twice weekly: 195±20 versus thrice weekly: 191±17 minutes). Plasma levels of the secreted solutes and β 2 microglobulin were not higher with twice weekly than thrice weekly hemodialysis.

Conclusions

Twice weekly hemodialysis can be prescribed using the higher contribution assigned to Kru by the 2015 KDOQI Guideline. With twice weekly hemodialysis, quality of life was unchanged, and the continuous function of the residual kidneys controlled fluid gain and plasma levels of potassium and uremic solutes without substantially longer treatment times.

Clinical Trial registration number:

NCT03874117.

Usefulness of the heart rate variability test in predicting intradialytic hypotension in patients undergoing chronic haemodialysis

Background

Intradialytic hypotension (IDH) is the primary complication of haemodialysis (HD); however, its diverse pathophysiology and inconsistent definitions complicate its prediction. Despite attempts using the heart rate variability (HRV) test for IDH prediction, studies on its usefulness for predicting IDH diagnosed per the nadir 90 criterion are lacking. We aimed to evaluate HRV test efficacy and reproducibility in predicting IDH based on the nadir 90 criterion.

Methods

Seventy patients undergoing HD participated in this multicentre prospective observational study. The HRV test was performed during non-HD periods and IDH was monitored during 12 HD sessions. IDH was diagnosed according to the nadir 90 criterion, defined as a decrease in systolic blood pressure of ≤90 mmHg during HD. After monitoring, the HRV test was repeated. An HRV-IDH index was developed using multivariate logistic regression analysis employing HRV test parameters. The predictive power of the HRV-IDH index was analysed using the area under the receiver operating characteristics curve (AUROC). Reproducibility was evaluated using correlation analysis of two HRV tests on the same patient.

Results

There were 37 and 33 patients in the IDH and non-IDH groups, respectively. The HRV-IDH index predicted IDH occurrence with AUROCs of 0.776 and 0.803 for patients who had experienced at least one or repeated IDH episodes, respectively. Spearman's correlation coefficient for HRV-IDH indices was 0.859 for the first and second HRV tests.

Conclusions

The HRV test holds promise for predicting IDH, particularly for patients with recurring IDH diagnosed based on the nadir 90 criterion.

Prospective Study of Modifiable Risk Factors of Arterial Hypertension and Left Ventricular Hypertrophy in Pediatric Patients on Hemodialysis

Introduction

Fluid and salt overload in patients on dialysis result in high blood pressure (BP), left ventricular hypertrophy (LVH) and hemodynamic instability, resulting in cardiovascular morbidity.

Methods

Analysis of 910 pediatric patients on maintenance hemodialysis/hemodiafiltration (HD/HDF), prospectively followed-up with 2758 observations recorded every 6-months in the International Pediatric Hemodialysis Network (IPHN).

Results

Uncontrolled hypertension was present in 55% of observations, with 27% of patients exhibiting persistently elevated predialysis BP. Systolic and diastolic age- and height-standardized BP (BP-SDS) were independently associated with the number of antihypertensive medications (odds ratio [OR] = 1.47, 95% confidence interval 1.39-1.56, 1.36 [1.23-1.36]) and interdialytic weight gain (IDWG; 1.19 [1.14-1.22], 1.09 [1.06-1.11]; all P < 0.0001). IDWG was related to urine output (OR = 0.27 [0.23-0.32]) and dialysate sodium (dNa; 1.06 [1.01-1.10]; all P < 0.0001). The prevalence of masked hypertension was 24%, and HD versus HDF use was an independent risk factor of elevated age- and height-standardized mean arterial pressure (MAP-SDS) (OR = 2.28 [1.18-4.41], P = 0.01). Of the 1135 echocardiograms, 51% demonstrated LVH. Modifiable risk factors included predialysis systolic BP-SDS (OR = 1.06 [1.04-1.09], P < 0.0001), blood hemoglobin (0.97 [0.95-0.99], P = 0.004), HD versus HDF modality (1.09 [1.02-1.18], P = 0.01), and IDWG (1.02 [1.02-1.03], P = 0.04). In addition, HD modality increased the risk of LVH progression (OR = 1.23 [1.03-1.48], P = 0.02). Intradialytic hypotension (IDH) was prevalent in patients progressing to LVH and independently associated with predialysis BP-SDS below 25th percentile, lower number of antihypertensives, HD versus HDF modality, ultrafiltration (UF) rate, and urine output, but not with dNa.

Conclusion

Uncontrolled hypertension and LVH are common in pediatric HD, despite intense pharmacologic therapy. The outcome may improve with use of HDF, and superior anemia and IDWG control; the latter via lowering dNa, without increasing the risk of IDH.

Hemodialysis Procedures for Stable Incident and Prevalent Patients Optimize Hemodynamic Stability, Dialysis Dose, Electrolytes, and Fluid Balance

The demographic profile of patients transitioning from chronic kidney disease to kidney replacement therapy is changing, with a higher prevalence of aging patients with multiple comorbidities such as diabetes mellitus and heart failure. Cardiovascular disease remains the leading cause of mortality in this population, exacerbated by the cardiovascular stress imposed by the HD procedure. The first year after transitioning to hemodialysis is associated with increased risks of hospitalization and mortality, particularly within the first 90-120 days, with greater vulnerability observed among the elderly. Based on data from clinics in Fresenius Medical Care Europe, Middle East, and Africa NephroCare, this review aims to optimize hemodialysis procedures to reduce mortality risk in stable incident and prevalent patients. It addresses critical aspects such as treatment duration, frequency, choice of dialysis membrane, dialysate composition, blood and dialysate flow rates, electrolyte composition, temperature control, target weight management, dialysis adequacy, and additional protocols, with a focus on mitigating prevalent intradialytic complications, particularly intradialytic hypotension prevention.

Comparison of blood volume biofeedback hemodialysis and conventional hemodialysis on cardiovascular stability and blood pressure control in hemodialysis patients: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Despite the improvements in hemodialysis (HD) technology, 20-30% of sessions are still complicated by hypotension or hypotension-related symptoms. Biofeedback systems have proven to reduce the occurrence of such events, but no conclusive findings can lead to wider adoption of these systems. We conducted this systematic review and meta-analysis of randomized clinical trials to establish whether the use of blood volume tracking systems compared to conventional hemodialysis (C-HD) reduces the occurrence of intradialytic hypotension.

METHODS

The PRISMA guidelines were used to carry out this systematic review. Randomized clinical trials that evaluated the incidence of intradialytic hypotension during C-HD and blood volume tracking-HD were searched in the current literature. PROSPERO registration number: CRD42023426328.

RESULTS

Ninety-seven randomized clinical trials were retrieved. Nine studies, including 347 participants and 13,274 HD treatments were considered eligible for this systematic review. The results showed that the use of biofeedback systems reduces the risk of intradialytic hypotension (log odds ratio = 0.63, p = 0.03) in hypotension-prone patients (log odds ratio = 0.54, p = 0.04). When analysis was limited to fluid overloaded or hypertensive patients, it did not show the same effect (log odds ratio = 0.79, p = 0.38). No correlation was found in systolic blood pressure drop during dialysis and in post-dialysis blood pressure.

CONCLUSIONS

The use of blood volume tracking systems may be effective in reducing the incidence of intradialytic hypotension and allowing for easier attainment of the patients' ideal dry body weight. New studies to examine the long-term effects of the use of blood volume tracking systems on real hard endpoints are needed.

Effects of Kt/Vurea on outcomes according to age in patients on maintenance hemodialysis

Background

The guidelines recommended target and minimum single-pool Kt/Vurea are 1.4 and 1.2, respectively, in hemodialysis patients. However, the optimal hemodialysis dose remains controversial. We investigated the effects of Kt/Vurea on patient outcomes according to age, with a focus on older patients.

Methods

This study used the hemodialysis quality assessment program and claims datasets. Patients were divided into four subgroups according to age (<65, 65-74, 75-84, and ≥85 years). Each group was divided into three subgroups according to Kt/Vurea : reference (ref) (1.2 ≤ Kt/Vurea ≤ 1.4), low (< 1.2), and high (> 1.4).

Results

The low, ref, and high Kt/Vurea groups included 1668, 8156, and 16 546 (< 65 years); 474, 3058, and 7646 (65-74 years); 225, 1362, and 4194 (75-84 years); and 14, 126, and 455 (≥85 years) patients, respectively. The low Kt/Vurea group had higher mortality rates than the ref Kt/Vurea group irrespective of age [adjusted hazard ratio (aHR), 95% confidence interval (CI): 1.23, 1.11-1.36; 1.14, 1.00-1.30; 1.28, 1.09-1.52; and 2.10, 1.16-3.98, in patients aged <65, 65-74, 75-84, and ≥85 years, respectively]. The high Kt/Vurea group had lower mortality rates than the ref Kt/Vurea group in patients aged <65 and 65-74 years (aHR, 95% Cl: 0.87, 0.82-0.92 and 0.93, 0.87-0.99 in patients aged <65 and 65-74 years, respectively).

Conclusions

These results support the current recommendations of a minimum Kt/Vurea of 1.2 even in patients age ≥85 years. In young patients, Kt/Vurea above the recommended threshold can be beneficial for survival.

Development and validation of a model for predicting the risk of cardiovascular events in maintenance hemodialysis patients

The mortality rates for patients undergoing hemodialysis (HD) remain unacceptably high compared to the general population, and more specific information about the causes of death is not known. The study aimed to develop and validate a risk prediction model that uses common clinical factors to predict the probability of cardiovascular events in maintenance hemodialysis (MHD) patients. The study involved 3488 adult patients who received regular scheduled hemodialysis treatment at 20 hemodialysis centers in southwest China between June 2015 and August 2020, with follow-up until August 2021. The optimal parameter set was identified by multivariable Cox regression analyses and Cross-LASSO regression analyses and was used to establish a nomogram for predicting the risk of cardiovascular events in maintenance hemodialysis patients at 3 and 5 years. The performance of the model was evaluated using the consistency index (Harrell's C-index), the area under the receiver operating characteristic (ROC) curve, and calibration plots. The model was validated by tenfold cross-validation and bootstrapping with 1000 resamples. In the derivation cohort, the model yields an AUC of 0.764 [95% confidence interval (CI), 0.737-0.790] and 0.793 [CI, 0.757-0.829] for predicting the risk of cardiovascular events of MHD patients at 3 and 5 years. In the internal validation cohort AUC of 0.803 [95% CI, 0.756-0.849], AUC of 0.766 [95% CI, 0.686-0.846], and the external validation cohort AUC of 0.826 [95% CI, 0.765-0.888], AUC of 0.817 [95% CI, 0.745-0.889] at 3 and 5 years. The model's calibration curve is close to the ideal diagonal. By tenfold cross-validation analyses, the 3- and 5-year risk of cardiovascular events (AUC 0.732 and 0.771, respectively). By the bootstrap resampling method, the derivation cohort and validation cohort (Harrell's C-index 0.695 and 0.667, respectively) showed good uniformity with the model. The constructed model accurately predicted cardiovascular events of MHD patients in the 3rd and 5th years after dialysis. And the further research is needed to determine whether use of the risk prediction tool improves clinical outcomes.

Transcatheter aortic valve replacement in patients with severe aortic stenosis reduced the frequency of intradialytic hypotension

Intradialytic hypotension (IDH) is a common complication during hemodialysis that increases cardiovascular morbidity and mortality. Aortic stenosis (AS) is a cause of IDH. Transcatheter aortic valve replacement (TAVR) has become an established treatment for patients with severe AS. However, whether TAVR reduce the frequency of IDH has not been investigated. This study aims to verify the efficacy of TAVR for reduction of the frequency of IDH. Consecutive hemodialysis patients who underwent TAVR at Sendai Kosei Hospital from February 2021 to November 2021 with available records 1 month before and 3 months after TAVR were included in the study. IDH was defined as a decrease in systolic blood pressure by 20 mmHg or a decrease in the mean blood pressure by 10 mmHg associated with hypotensive symptoms or requiring intervention. Patients with ≥ 3 episodes of IDH in ten hemodialysis sessions comprised the IDH group. Overall, 18/41 (43.9%) patients were classified into the IDH group. In ten hemodialysis sessions, IDH events were observed 2.1, 4.3, and 0.4 times in the overall cohort, IDH group, and non-IDH group, respectively. After TAVR, the incidence of IDH decreased from 43.2 to 10.3% (p < 0.0001) and IDH improved significantly in 15 patients in the IDH group. The result suggested that severe AS was the major cause of IDH in this cohort, and TAVR may be an effective treatment option for reduction of the frequency of IDH in patients with severe AS.

Effect of Dialysate and Plasma Sodium on Mortality in a Global Historical Hemodialysis Cohort

SIGNIFICANCE STATEMENT

This large observational cohort study aimed to investigate the relationship between dialysate and plasma sodium concentrations and mortality among maintenance hemodialysis patients. Using a large multinational cohort of 68,196 patients, we found that lower dialysate sodium concentrations (≤138 mmol/L) were independently associated with higher mortality compared with higher dialysate sodium concentrations (>138 mmol/L). The risk of death was lower among patients exposed to higher dialysate sodium concentrations, regardless of plasma sodium levels. These results challenge the prevailing assumption that lower dialysate sodium concentrations improve outcomes in hemodialysis patients. The study confirms that until robust evidence from randomized trials that are underway is available, nephrologists should remain cautious in reconsideration of dialysate sodium prescribing practices to optimize cardiovascular outcomes and reduce mortality in this population.

BACKGROUND

Excess mortality in hemodialysis (HD) patients is largely due to cardiovascular disease and is associated with abnormal fluid status and plasma sodium concentrations. Ultrafiltration facilitates the removal of fluid and sodium, whereas diffusive exchange of sodium plays a pivotal role in sodium removal and tonicity adjustment. Lower dialysate sodium may increase sodium removal at the expense of hypotonicity, reduced blood volume refilling, and intradialytic hypotension risk. Higher dialysate sodium preserves blood volume and hemodynamic stability but reduces sodium removal. In this retrospective cohort, we aimed to assess whether prescribing a dialysate sodium ≤138 mmol/L has an effect on survival outcomes compared with dialysate sodium >138 mmol/L after adjusting for plasma sodium concentration.

METHODS

The study population included incident HD patients from 875 Fresenius Medical Care Nephrocare clinics in 25 countries between 2010 and 2019. Baseline dialysate sodium (≤138 or >138 mmol/L) and plasma sodium (<135, 135-142, >142 mmol/L) concentrations defined exposure status. We used multivariable Cox regression model stratified by country to model the association between time-varying dialysate and plasma sodium exposure and all-cause mortality, adjusted for demographic and treatment variables, including bioimpedance measures of fluid status.

RESULTS

In 2,123,957 patient-months from 68,196 incident HD patients with on average three HD sessions per week dialysate sodium of 138 mmol/L was prescribed in 63.2%, 139 mmol/L in 15.8%, 140 mmol/L in 20.7%, and other concentrations in 0.4% of patients. Most clinical centers (78.6%) used a standardized concentration. During a median follow-up of 40 months, one third of patients ( n =21,644) died. Dialysate sodium ≤138 mmol/L was associated with higher mortality (multivariate hazard ratio for the total population (1.57, 95% confidence interval, 1.25 to 1.98), adjusted for plasma sodium concentrations and other confounding variables. Subgroup analysis did not show any evidence of effect modification by plasma sodium concentrations or other patient-specific variables.

CONCLUSIONS

These observational findings stress the need for randomized evidence to reliably define optimal standard dialysate sodium prescribing practices.

Higher NT-proBNP levels and the risk of intradialytic hypotension at hemodialysis initiation

INTRODUCTION

Elevated N-terminal pro B-type natriuretic peptide (NT-proBNP) is a potent predictor of adverse outcomes in hemodialysis initiation. These patients often experience intradialytic hypotension, which may partially reflect cardiac dysfunction, but the association of NT-proBNP with intradialytic hypotension is not clear.

METHODS

We performed a post hoc analysis of a randomized trial that tested mannitol versus placebo in 52 patients initiating hemodialysis (NCT01520207). NT-proBNP was measured prior to the first and third sessions (n = 87). Mixed-effects models (adjusting for randomized treatment, sex, race, age, diabetes, heart failure, catheter use, pre-dialysis systolic blood pressure, pre-dialysis weight, ultrafiltration volume, serum sodium, bicarbonate, urea nitrogen, phosphate, albumin, hemoglobin, and session length) were fit to examine the association of NT-proBNP with systolic blood pressure decline (pre-dialysis minus nadir systolic blood pressure). Additionally, mixed-effects Poisson models were fit to examine the association with intradialytic hypotension (≥20 mmHg decline in systolic blood pressure).

FINDINGS

Mean age was 55 ± 16 years; 33% had baseline heart failure. The median NT-proBNP was 5498 [25th-75th percentile 2011, 14,790] pg/mL; 26 sessions (30%) were complicated by intradialytic hypotension. In adjusted models, each unit higher log-NT-proBNP was associated with 6.0 mmHg less decline in systolic blood pressure (95%CI -9.2 to -2.8). Higher pre-dialysis NT-proBNP, per log-unit, was associated with a 52% lower risk of intradialytic hypotension (IRR 0.48, 95%CI 0.23-0.97), without evidence for effect modification by randomized treatment (P-interaction = 0.17).

DISCUSSION

In patients initiating hemodialysis, higher NT-proBNP is associated with less decline in intradialytic systolic blood pressure and lower risk of intradialytic hypotension. Future studies should investigate if higher pre-dialysis NT-proBNP levels may identify patients who might tolerate more aggressive ultrafiltration.

Comparison of whole body versus thoracic bioimpedance in relation to ultrafiltration volume and systolic blood pressure during hemodialysis

In contrast to whole body bioimpedance, which estimates fluid status at a single point in time, thoracic bioimpedance applied by a wearable device could enable continuous measurements. However, clinical experience with thoracic bioimpedance in patients on dialysis is limited. To test the reproducibility of whole body and thoracic bioimpedance measurements and to compare their relationship with hemodynamic changes during hemodialysis, these parameters were measured pre- and end-dialysis in 54 patients during two sessions. The resistance from both bioimpedance techniques was moderately reproducible between two dialysis sessions (intraclass correlations of pre- to end-dialysis whole body and thoracic resistance between session 1 and 2 were 0.711 [0.58-0.8] and 0.723 [0.6-0.81], respectively). There was a very high to high correlation between changes in ultrafiltration volume and changes in whole body thoracic resistance. Changes in systolic blood pressure negatively correlated to both bioimpedance techniques. Although the relationship between changes in ultrafiltration volume and changes in resistance was stronger for whole body bioimpedance, the relationship with changes in blood pressure was at least comparable for thoracic measurements. These results suggest that thoracic bioimpedance, measured by a wearable device, may serve as an interesting alternative to whole body measurements for continuous hemodynamic monitoring during hemodialysis.NEW & NOTEWORTHY We examined the role of whole body and thoracic bioimpedance in hemodynamic changes during hemodialysis. Whole body and thoracic bioimpedance signals were strongly related to ultrafiltration volume and moderately, negatively, to changes in blood pressure. This work supports the further development of a wearable device measuring thoracic bioimpedance longitudinally in patients on hemodialysis. As such, it may serve as an innovative tool for continuous hemodynamic monitoring during hemodialysis in hospital or in a home-based setting.

National Trends in Mortality and Urgent Dialysis after Acute Hypertension in Japan From 2010 Through 2019

BACKGROUND

Despite increasing incidences of hypertension, recent trends in mortality and urgent dialysis following acute hypertension (AHT) remain undetermined.

METHODS

This retrospective observational cohort study evaluated 50 316 hospitalized AHT patients from 2010 to 2019, using an administrative claims database in Japan. We examined trends in incidence, urgent dialysis, mortality, and its risk factors using Poisson regression models. Using International Classification of Disease and Related Health Problems, 10th Revision codes, AHT was categorized into 5 spectrums: malignant hypertension (n=1792), hypertensive emergency (n=17 907), hypertensive urgency (n=1562), hypertensive encephalopathy (n=6593), and hypertensive heart failure (HHF; n=22 462).

RESULTS

The median age of the patients was 76 years, and 54.9% were women. The total AHT incidence was 70 cases per 100 000 admission year. The absolute death rate increased from 1.83% (95% CI, 1.40-2.40) to 2.88% ([95% CI, 2.42-3.41]; Cochran-Armitage trend test, P<0.0001). Upward trends were observed in patients aged ≥80, with lean body mass index ≤18.4, and with HHF. Urgent dialysis rates increased from 1.52% (95% CI, 1.12-2.06) to 2.60% (2.17-3.1; Cochran-Armitage trend test; P=0.0071) in 48 235 patients, excluding maintenance dialysis patients. Older age, men, lean body mass, malignant hypertension, HHF, and underlying chronic kidney disease correlated with higher mortality risk; greater hospital volume correlated with lower mortality risk; and malignant hypertension, HHF, diabetes, chronic kidney disease, and scleroderma correlated with a higher risk of urgent dialysis.

CONCLUSIONS

Mortality and urgent dialysis rates following AHT have increased. Aging, complex comorbidities, and HHF-type AHT contributed to the rising trend of mortality.

Early Net Ultrafiltration during Continuous Renal Replacement Therapy: Impact of Admission Diagnosis and Association with Mortality

INTRODUCTION

Continuous renal replacement therapy (CRRT) is common in the intensive care unit (ICU) but a high net ultrafiltration rate (UFNET) calculated with daily data may increase mortality. We aimed to study early UFNET practice using minute-by-minute CRRT machine recordings and to assess its association with admission diagnosis and mortality.

METHODS

We studied CRRT treatments in three adult ICUs over 7 years. We calculated early UFNET rates minute-by-minute and categorized UFNET into tertiles of mean UFNET in the first 72 h and admission diagnosis. We applied Cox-proportional hazards modelling with censoring of patients who died within 72 h.

RESULTS

We studied 1,218 patients, 154,712 h, and 9,282,729 min of CRRT (5,702 circuits). Mean early UFNET was 1.52 (1.46-1.57) mL/kg/h. Early UFNET tertiles were similar to, but somewhat higher than, previously reported values at 0.00-1.20 mL/kg/h, 1.21-1.93 mL/kg/h, and >1.93 mL/kg/h. UFNET values were similar whether evaluated at 24 or 72 h or for the entire duration of CRRT. There was, however, significant variation in UFNET practice by admission diagnosis: higher in respiratory diseases (pneumonia p = 0.01, other p < 0.0001) and cardiovascular disease (p = 0.005) but lower in cardiothoracic surgery (p = 0.04), renal (p = 0.0003) and toxicology-associated diagnoses (p = 0.01). Higher UFNET was associated with an increased hazard of death, HR 1.24 (1.13-1.37), independent of admission diagnosis, weight, age, sex, presence of end-stage kidney disease, and severity of illness.

CONCLUSION

Early UFNET practice varies significantly by admission diagnosis. Higher early UFNET is independently associated with mortality. Impacts of UFNET on mortality may vary by admission diagnosis. Further work is required to elucidate the nature and mechanisms responsible for this association.

Day-to-day variability in euvolemic body mass

Short-term variability in body mass is a common, everyday phenomenon; however, data on body mass variability are scarce. While the physiological variability of body mass is negligible in healthy individuals, it could have implications for therapy in patients with impaired volume homeostasis, for example, patients with kidney failure undergoing kidney replacement therapy. We analyzed a long-term dataset comprising 9521 days of standardized body mass measurements from one healthy male individual and assessed the variability in body mass as a positive or negative relative difference in body mass measured on subsequent days. The average and median relative differences were zero, with a standard deviation (SD) of 0.53% for the one-day interval, increasing to 0.69% for the 7-day interval, and this variability was constant throughout the observation period. A body mass variability of approximately 0.6% (±450 mL in a 75-kg patient) should be taken into consideration when weight-dependent treatment prescriptions, e.g. the ultrafiltration rates in patients on hemodialysis, are being set. Consequently, a "soft target weight", considering the longitudinal variation of volume markers, such as body mass, might improve treatment quality.

Accuracy of Crit-Line® monitors in predicting hematocrit and change in blood volume of dogs during hemodialysis

BACKGROUND

Ultrafiltration (UF) is an extracorporeal technique for treating fluid overload and is monitored with noninvasive blood volume monitors.

HYPOTHESIS/OBJECTIVES

The primary objective was to determine the accuracy of Crit-Line® III and IV noninvasive blood volume monitors to estimate canine packed cell volume (PCV) and changes in blood volume during UF. A secondary aim was to determine accuracy of targeted ultrafiltration rates (UFR) compared to calculated delivered UFR.

METHODS

An ex vivo study with a single Phoenix® X36 platform and canine packed red blood cells (pRBC) was performed. Through dilution and UF, clinically applicable PCV values were obtained and compared to Crit-Line® hematocrit (Hct). Blood volume was constantly measured and compared to targeted UFR. Systematic and proportional bias were calculated using a Bayes method.

RESULTS

Crit-Line® III and IV reported Hct was significantly lower than PCV (n = 140, median 26%, range, 8%-50%) when PCV was >25% and >30%, respectively. Crit-Line® III and IV calculated change in blood volume (ΔBV%) was significantly different from measured blood volume changes at ΔBV% ±20% and >-20%, respectively. Comparing targeted and delivered UFR (mL/h), less than targeted UFR was removed at UFR100 through UFR400 and UFR0 adding volume.

CONCLUSIONS AND CLINICAL IMPORTANCE

Crit-Line® III and IV monitors provide accurate estimates of canine PCV and UF volume change within specific ranges and are useful in monitoring canine UF and hemodialysis. Veterinary hemodialysis services should evaluate individual machines for UFR inaccuracies, which can meaningfully affect small animals.

Point-of-Care Chemistry-Guided Dialysate Adjustment to Reduce Arrhythmias: A Pilot Trial

Introduction

Excessive dialytic potassium (K) and acid removal are risk factors for arrhythmias; however, treatment-to-treatment dialysate modification is rarely performed. We conducted a multicenter, pilot randomized study to test the safety, feasibility, and efficacy of 4 point-of-care (POC) chemistry-guided protocols to adjust dialysate K and bicarbonate (HCO3) in outpatient hemodialysis (HD) clinics.

Methods

Participants received implantable cardiac loop monitors and crossed over to four 4-week periods with adjustment of dialysate K or HCO3 at each treatment according to pre-HD POC values: (i) K-removal minimization, (ii) K-removal maximization, (iii) Acidosis avoidance, and (iv) Alkalosis avoidance. The primary end point was percentage of treatments adhering to the intervention algorithm. Secondary endpoints included pre-HD K and HCO variability, adverse events, and rates of clinically significant arrhythmias (CSAs).

Results

Nineteen subjects were enrolled in the study. HD staff completed POC testing and correctly adjusted the dialysate in 604 of 708 (85%) of available HD treatments. There was 1 K ≤3, 29 HCO3 <20 and 2 HCO3 >32 mEq/l and no serious adverse events related to study interventions. Although there were no significant differences between POC results and conventional laboratory measures drawn concurrently, intertreatment K and HCO3 variability was high. There were 45 CSA events; most were transient atrial fibrillation (AF), with numerically fewer events during the alkalosis avoidance period (8) and K-removal maximization period (3) compared to other intervention periods (17). There were no significant differences in CSA duration among interventions.

Conclusion

Algorithm-guided K/HCO3 adjustment based on POC testing is feasible. The variability of intertreatment K and HCO3 suggests that a POC-laboratory-guided algorithm could markedly alter dialysate-serum chemistry gradients. Definitive end point-powered trials should be considered.

Novel Therapeutic Approaches in the Management of Chronic Kidney Disease

Chronic kidney disease (CKD) is a progressive and incurable disease that impairs kidney function. Its prevalence is estimated to affect up to 800 million individuals within the general population, and patients with diabetes and hypertension are particularly at risk. This disorder disrupts the physiological mechanisms of the body, including water and electrolyte balance, blood pressure regulation, the excretion of toxins, and vitamin D metabolism. Consequently, patients are exposed to risks such as hyperkalemia, hyperphosphatemia, metabolic acidosis, and blood pressure abnormalities. These risks can be reduced by implementing appropriate diagnostic methods, followed by non-pharmacological (such as physical activity, dietary, and lifestyle adjustment) and pharmacological strategies after diagnosis. Selecting the appropriate diet and suitable pharmacological treatment is imperative in maintaining kidney function as long as possible. Drugs such as finerenone, canakinumab, and pentoxifylline hold promise for improved outcomes among CKD patients. When these interventions prove insufficient, renal replacement therapy becomes essential. This is particularly critical in preserving residual renal function while awaiting renal transplantation or for patients deemed ineligible for such a procedure. The aim of this study is to present the current state of knowledge and recent advances, providing novel insights into the treatment of chronic kidney disease.

Machine learning-based intradialytic hypotension prediction of patients undergoing hemodialysis: A multicenter retrospective study

BACKGROUND AND OBJECTIVE

Intradialytic hypotension (IDH) is closely associated with adverse clinical outcomes in HD-patients. An IDH predictor model is important for IDH risk screening and clinical decision-making. In this study, we used Machine learning (ML) to develop IDH model for risk prediction in HD patients.

METHODS

62,227 dialysis sessions were randomly partitioned into training data (70%), test data (20%), and validation data (10%). IDH-A model based on twenty-seven variables was constructed for risk prediction for the next HD treatment. IDH-B model based on ten variables from 64,870 dialysis sessions was developed for risk assessment before each HD treatment. Light Gradient Boosting Machine (LightGBM), Linear Discriminant Analysis, support vector machines, XGBoost, TabNet, and multilayer perceptron were used to develop the predictor model.

RESULTS

In IDH-A model, we identified the LightGBM method as the best-performing and interpretable model with C- statistics of 0.82 in Fall30Nadir90 definitions, which was higher than those obtained using the other models (P<0.01). In other IDH standards of Nadir90, Nadir100, Fall20, Fall30, and Fall20Nadir90, the LightGBM method had a performance with C- statistics ranged 0.77 to 0.89. As a complementary application, the LightGBM model in IDH-B model achieved C- statistics of 0.68 in Fall30Nadir90 definitions and 0.69 to 0.78 in the other five IDH standards, which were also higher than the other methods, respectively.

CONCLUSION

Use ML, we identified the LightGBM method as the good-performing and interpretable model. We identified the top variables as the high-risk factors for IDH incident in HD-patient. IDH-A and IDH-B model can usefully complement each other for risk prediction and further facilitate timely intervention through applied into different clinical setting.

Prevention of Intradialytic Hypotension in Hemodialysis Patients: Current Challenges and Future Prospects

Intradialytic hypotension, defined as rapid decrease in systolic blood pressure of greater than or equal to 20 mmHg or in mean arterial pressure of greater than or equal to 10 mmHg that results in end-organ ischemia and requires countermeasures such as ultrafiltration reduction or saline infusion to increase blood pressure to improve patient's symptoms, is a known complication of hemodialysis and is associated with several potential adverse outcomes. Its pathogenesis is complex and involves both patient-related factors such as age and comorbidities, as well as factors related to the dialysis prescription itself. Key factors include the need for volume removal during hemodialysis and a suboptimal vascular response which compromises the ability to compensate for acute intravascular volume loss. Inadequate vascular refill, incorrect assessment or unaccounted changes of target weight, acute illnesses and medication interference are further potential contributors. Intradialytic hypotension can lead to compromised tissue perfusion and end-organ damage, both acutely and over time, resulting in repetitive injuries. To address these problems, a careful assessment of subjective symptoms, minimizing interdialytic weight gains, individualizing dialysis prescription and adjusting the dialysis procedure based on patients' risk factors can mitigate negative outcomes.

Differences between Hepatic and Cerebral Regional Tissue Oxygen Saturation at the Onset of Intradialytic Hypotension

BACKGROUND

Intradialytic hypotension (IDH) is a critical pathological condition associated with all-cause mortality in patients undergoing hemodialysis (HD). However, few studies have investigated IDH-related changes in hepatic and cerebral regional tissue oxygen saturation (rSO2). This study investigated IDH-induced changes in hepatic and cerebral rSO2.

METHODS

Hepatic and cerebral rSO2 during HD were measured using an INVOS 5100C oxygen saturation monitor, and their percentage (%) changes during the development of IDH were analyzed. Ninety-one patients undergoing HD were investigated, including twenty with IDH.

RESULTS

In patients with IDH, % changes in hepatic and cerebral rSO2 decreased at the onset of IDH. Additionally, the % change in hepatic rSO2 was significantly larger than that in cerebral rSO2 (p < 0.001). In patients without IDH, no significant differences were found between the % changes in hepatic and cerebral rSO2 at the time of the lowest systolic blood pressure during HD. Multivariable linear regression analysis showed that the difference between the % changes in cerebral and hepatic rSO2 was significantly associated with the development of IDH (p < 0.001) and the ultrafiltration rate (p = 0.010).

CONCLUSIONS

Hepatic and cerebral rSO2 significantly decreased during the development of IDH, and hepatic rSO2 was more significantly decreased than cerebral rSO2 at the onset of IDH.

Bioimpedanciometry in nutritional and hydration assessments in a single dialysis center

BACKGROUND

Bioimpedance analysis (BIA) has been demonstrated to add accuracy to nutritional and volume status assessments in dialysis (HD) patients.

AIM

to describe a sample of dialysis patients from a single center on their demographics and BIA of volume distribution and nutritional status, and mortality during 12-month follow-up.

METHODS

prospective observational cohort study to evaluate vintage HD patients with single-frequency BIA.

RESULTS

we evaluated 82 patients, 29% over 65 years old. Elderly patients had higher ECW/TBW (0.51 vs. 0.44, p < 0.0001), and narrower phase angle (PhA) (4.9 vs. 6.4º, p < 0.0001). Fifteen patients (18.2%) died during follow-up, eight (53%) were elderly. Death was associated with age (62.6 vs. 50.2 years, p = 0.012), post-HD PhA (4.8 vs. 6.2º, p = 0.0001), and post-HD ECW/TBW (0.50 vs. 0.45, p = 0.015). The ROC curve analysis to predict mortality found ECW/TBW ≥ 0.47 and PhA ≤ 5.5º to have the best sensitivity and specificity. One-year patient survival was lower with post-HD ECW/TBW ≥ 0.47 (69.5% vs. 90.6%, p = 0.019), age ≥ 65 years (64.2%, vs. 86.2%, p = 0.029), and PhA ≤ 5.5º (68.2 vs. 91.0%, p = 0.002). Cox regression analysis demonstrated that PhA [HR 5.04 (95%CI 1.60-15.86), p = 0.006] remained associated with death after adjusting for age and ECW/TBW.

CONCLUSION

BIA is useful in assessing volume distribution and nutrition in HD patients, and combined with clinical judgement, may help determine dry weight, especially in elderly patients. Narrower PhA and higher ECW/TBW after HD were associated with poorer one-year survival.

Management of Cardiovascular Diseases in Chronic Hemodialysis Patients

Hemodialysis (HD) is the main treatment modality for patients with end-stage kidney disease. Cardiovascular diseases (CVD) are highly prevalent in HD patients and are the leading cause of death in this population, with the mortality from CVD approximately 20 times higher than that of the general population. Traditional and non-traditional cardiovascular risk factors accelerate progression of CVD and exacerbate the prognosis in HD patients. This review provides a brief overview of the characteristics of CVD in HD patients, and a description of advances in its management.

Results of Salt Intake Restriction Monitored with the New Sodium Control Biosensor

INTRODUCTION

Adherence to a low-sodium (Na) diet is crucial in patients under hemodialysis, as it improves cardiovascular outcomes and reduces thirst and interdialytic weight gain. Recommended salt intake is lower than 5 g/day. The new 6008 CAREsystem monitors incorporate a Na module that offers the advantage of estimating patients' salt intake. The objective of this study was to evaluate the effect of dietary Na restriction for 1 week, monitored with the Na biosensor.

METHODS

A prospective study was conducted in 48 patients who maintained their usual dialysis parameters and were dialyzed with a 6008 CAREsystem monitor with activation of the Na module. Total Na balance, pre-/post-dialysis weight, serum Na (sNa), changes in pre- to post-dialysis sNa (ΔsNa), diffusive balance, and systolic and diastolic blood pressure were compared twice, once after 1 week of patients' usual Na diet and again after another week with more restricted Na intake.

RESULTS

Restricted Na intake increased the percentage of patients on a low-Na diet (<85 Na mmol/day) from 8% to 44%. Average daily Na intake decreased from 149 ± 54 to 95 ± 49 mmol, and interdialytic weight gain was reduced by 460 ± 484 g per session. More restricted Na intake also decreased pre-dialysis sNa and increased both intradialytic diffusive balance and ΔsNa. In hypertensive patients, reducing daily Na by more than 3 g Na/day lowered their systolic blood pressure.

CONCLUSIONS

The new Na module allowed objective monitoring of Na intake, which in turn could permit more precise personalized dietary recommendations in patients under hemodialysis.

Ultrafiltration Rate Levels in Hemodialysis Patients Associated with Weight-Specific Mortality Risks

BACKGROUND

We hypothesized that the association of ultrafiltration rate with mortality in hemodialysis patients was differentially affected by weight and sex and sought to derive a sex- and weight-indexed ultrafiltration rate measure that captures the differential effects of these parameters on the association of ultrafiltration rate with mortality.

METHODS

Data were analyzed from the US Fresenius Kidney Care (FKC) database for 1 year after patient entry into a FKC dialysis unit (baseline) and over 2 years of follow-up for patients receiving thrice-weekly in-center hemodialysis. To investigate the joint effect of baseline-year ultrafiltration rate and postdialysis weight on survival, we fit Cox proportional hazards models using bivariate tensor product spline functions and constructed contour plots of weight-specific mortality hazard ratios over the entire range of ultrafiltration rate values and postdialysis weights (W).

RESULTS

In the studied 396,358 patients, the average ultrafiltration rate in ml/h was related to postdialysis weight (W) in kg: 3W+330. Ultrafiltration rates associated with 20% or 40% higher weight-specific mortality risk were 3W+500 and 3W+630 ml/h, respectively, and were 70 ml/h higher in men than in women. Nineteen percent or 7.5% of patients exceeded ultrafiltration rates associated with a 20% or 40% higher mortality risk, respectively. Low ultrafiltration rates were associated with subsequent weight loss. Ultrafiltration rates associated with a given mortality risk were lower in high-body weight older patients and higher in patients on dialysis for more than 3 years.

CONCLUSIONS

Ultrafiltration rates associated with various levels of higher mortality risk depend on body weight, but not in a 1:1 ratio, and are different in men versus women, in high-body weight older patients, and in high-vintage patients.

Dynamics of Plasma Refill Rate and Intradialytic Hypotension During Hemodialysis: Retrospective Cohort Study With Causal Methodology

Key Points

Directly studying plasma refill rate (PRR) during hemodialysis (HD) can offer insight into physiologic mechanisms that change throughout HD. PRR at the start and during HD is associated with intradialytic hypotension, independent of ultrafiltration rate. A rising PRR during HD may be an early indicator of compensatory mechanisms for impending circulatory instability.

Background

Attaining the optimal balance between achieving adequate volume removal while preserving organ perfusion is a challenge for patients receiving maintenance hemodialysis (HD). Current strategies to guide ultrafiltration are inadequate.

Methods

We developed an approach to calculate the plasma refill rate (PRR) throughout HD using hematocrit and ultrafiltration data in a retrospective cohort of patients receiving maintenance HD at 17 dialysis units from January 2017 to October 2019. We studied whether (1 ) PRR is associated with traditional risk factors for hemodynamic instability using logistic regression, (2 ) low starting PRR is associated with intradialytic hypotension (IDH) using Cox proportional hazard regression, and (3 ) time-varying PRR throughout HD is associated with hypotension using marginal structural modeling.

Results

During 180,319 HD sessions among 2554 patients, PRR had high within-patient and between-patient variability. Female sex and hypoalbuminemia were associated with low PRR at multiple time points during the first hour of HD. Low starting PRR has a higher hazard of IDH, whereas high starting PRR was protective (hazard ratio [HR], 1.26, 95% confidence interval [CI], 1.18 to 1.35 versus HR, 0.79, 95% CI, 0.73 to 0.85, respectively). However, when accounting for time-varying PRR and time-varying confounders, compared with a moderate PRR, while a consistently low PRR was associated with increased risk of hypotension (odds ratio [OR], 1.09, 95% CI, 1.02 to 1.16), a consistently high PRR had a stronger association with hypotension within the next 15 minutes (OR, 1.38, 95% CI, 1.30 to 1.45).

Conclusions

We present a straightforward technique to quantify plasma refill that could easily integrate with devices that monitor hematocrit during HD. Our study highlights how examining patterns of plasma refill may enhance our understanding of circulatory changes during HD, an important step to understand how current technology might be used to improve hemodynamic instability.

Why is Intradialytic Hypotension the Commonest Complication of Outpatient Dialysis Treatments?

Intradialytic hypotension (IDH) is the most frequent complication of hemodialysis (HD) treatments with a frequency of 10% to 12% for patients with chronic kidney disease attending for outpatient treatments and is associated with both temporary ischemic stress to vital organs, including the heart and brain, and increased patient mortality. Although there have been many different definitions of IDH over the years, an absolute nadir systolic blood pressure (SBP) has the strongest association with patient outcomes. The unifying pathophysiology is one of reduced effective blood volume, resulting in lower plasma tonicity, and if this cannot be adequately compensated for by activation of neurohumeral systems, then arteriolar tone and blood pressure fall. The risk factors for developing IDH are numerous, ranging from patient-related factors, including age and comorbidity with reduced cardiac reserve, to patient compliance with dietary and lifestyle advice, to reactions with the extracorporeal circuit and medications, choice of dialysate composition and temperature, setting of postdialysis target weight, ultrafiltration rate, and profiling. Advances in dialysis machine technology by providing real time estimates of the effective circulating volume and adjusting dialysate composition to maintain vascular tonicity are being developed, but currently require more sophisticated biofeedback loops to be clinically effective in preventing IDH. While awaiting advances in artificial intelligence, the clinician continues to rely on patient education to limit interdialytic weight gains, frequent assessment of the postdialysis target weight, adjusting dialysate composition and temperature, introducing convective therapies to increase thermal losses, and altering dialysis session duration and frequency to reduce ultrafiltration rate requirements.

Changes of Hemodynamic Parameters after Intradialytic Glucose Injection

BACKGROUND

Intradialytic hypotension (IDH) is a frequent complication of hemodialysis (HD). Current methods of IDH prevention are insufficient.

METHODS

We analyzed the intradialytic time course of systolic (SBP), diastolic (DBP), mean arterial (MAP), pulse pressure (PP), and heart rate (HR) in a group of chronic kidney disease (CKD) patients. First, 30 min into HD, a 40% glucose solution was injected into the venous line of the extracorporeal circulation at a dose of 0.5 g/kg of dry weight. Pressures and HR were measured in frequent intervals. Relative volume overload was determined by bioimpedance spectroscopy.

RESULTS

Thirty-five participants were studied. SBP increased after 5, 10, and 20 min of glucose infusion. DBP increased after 2 and 3 h and also at the end of HD. PP increased after 5, 10, and 20 min of glucose infusion and fell after the 2nd and 3rd hour and also at the end of HD. MAP increased after 2 and 3 h of glucose injection and at the end of HD. Significant interactions of the time course of SBP, DBP, MAP, with HR at baseline and of the time course of PP with fluid overload were observed. Symptomatic hypotensive episodes were absent.

CONCLUSIONS

Glucose infusions during HD prevent symptomatic IDH and do not cause severe hypertensive episodes.

Circumferential Strain as a Marker of Vessel Reactivity in Patients with Intradialytic Hypotension

Background and Objectives: Intradialytic hypotension (IDH) complicates 4 to 39.9% of hemodialysis (HD) sessions. Vessels' reactivity disturbances may be responsible for this complication. Two-dimensional speckle tracking is used to assess arterial circumferential strain (CS) as a marker of the effectiveness of the cardiovascular response to the reduction of circulating plasma. Materials and Methods: The common carotid artery (CCA) and common iliac artery (CIA) CSs were recorded using ultrasonography in 68 chronically dialyzed patients before and after one HD session. Results: In patients with IDH episodes (n = 26), the CCA-CS was significantly lower both before (6.28 ± 2.34 vs. 4.63 ± 1.74 p = 0.003) and after HD (5.00 (3.53-6.78) vs. 3.79 ± 1.47 p = 0.010) than it was in patients without this complication. No relationship was observed between CIA-CS and IDH. IDH patients had a significantly higher UF rate; however, they did not differ compared to complication-free patients either in anthropometric or laboratory parameters. Conclusions: Patients with IDH were characterized by lower pre- and post-HD circumferential strain of the common carotid artery. The lower CCA-CS showed that impaired vascular reactivity is one of the most important risk factors for this complication's occurrence.

Pilot Study of a Wearable Hydration Monitor in Haemodialysis Patients: Haemodialysis Outcomes & Patient Empowerment Study 02

Introduction

We aimed to assess the validity and reproducibility of a wearable hydration device in a cohort of maintenance dialysis patients.

Methods

We conducted a prospective, single-arm observational study on 20 haemodialysis patients between January and June 2021 in a single centre. A prototype wearable infrared spectroscopy device, termed the Sixty device, was worn on the forearm during dialysis sessions and nocturnally. Bioimpedance measurements were performed 4 times using the body composition monitor (BCM) over 3 weeks. Measurements from the Sixty device were compared with the BCM overhydration index (litres) pre- and post-dialysis and with standard haemodialysis parameters.

Results

12 out of 20 patients had useable data. Mean age was 52 ± 12.4 years. The overall accuracy for predicting pre-dialysis categories of fluid status using Sixty device was 0.55 [K = 0.00; 95% CI: -0.39-0.42]. The accuracy for the prediction of post-dialysis categories of volume status was low [accuracy = 0.34, K = 0.08; 95% CI: -0.13-0.3]. Sixty outputs at the start and end of dialysis were weakly correlated with pre- and post-dialysis weights (r = 0.27 and r = 0.27, respectively), as well as weight loss during dialysis (r = 0.31), but not ultrafiltration volume (r = 0.12). There was no difference between the change in Sixty readings overnight and the change in Sixty readings during dialysis (mean difference 0.09 ± 1.5 kg), [t(39) = 0.38, p = 0.71].

Conclusion

A prototype wearable infrared spectroscopy device was unable to accurately assess changes in fluid status during or between dialysis sessions. In the future, hardware development and advances in photonics may enable the tracking of interdialytic fluid status.

High Ultrafiltration Rate Is Associated with Increased All-Cause Mortality in Incident Hemodialysis Patients with a High Cardiothoracic Ratio

A high ultrafiltration rate (UFR) is associated with increased mortality in hemodialysis patients. However, whether a high UFR itself or heart failure with fluid overload followed by a high UFR causes mortality remains unknown. In this study, 2615 incident hemodialysis patients were categorized according to their initial cardiothoracic ratios (CTRs) to assess whether UFR was associated with mortality in patients with high or low CTRs. In total, 1317 patients (50.4%) were women and 1261 (48.2%) were diabetic. During 2246 (1087−3596) days of follow-up, 1247 (47.7%) cases of all-cause mortality were noted. UFR quintiles 4 and 5 were associated with higher risks of all-cause mortality than UFR quintile 2 in fully adjusted Cox regression analysis. As the UFR increased by 1 mL/kg/h, the risk of all-cause mortality increased 1.6%. Subgroup analysis revealed that in UFR quintile 5, hazard ratios (HRs) for all-cause mortality were 1.91, 1.48, 1.22, and 1.10 for CTRs of >55%, 50−55%, 45−50%, and <45%, respectively. HRs for all-cause mortality were higher in women and patients with high body weight. Thus, high UFRs may be associated with increased all-cause mortality in incident hemodialysis patients with a high CTR, but not in those with a low CTR.

Bioimpedanciometria em avaliações nutricionais e de hidratação em um único centro de diálise

RESUMO Antecedentes: Análise de bioimpedância (BIA) demonstrou adicionar acurácia às avaliações de estado nutricional e de volume em pacientes em diálise (HD). Objetivo: descrever amostra de pacientes em diálise de um único centro quanto aos aspectos demográficos e BIA na distribuição de volume e no estado nutricional, e a mortalidade em 12 meses de acompanhamento. Métodos: estudo de coorte observacional prospectivo para avaliar pacientes prevalentes em HD com BIA de frequência única. Resultados: avaliamos 82 pacientes, 29% acima de 65 anos. Pacientes idosos apresentaram maior AEC/ACT (0,51 vs. 0,44; p < 0,0001), e ângulo de fase mais estreito (PhA) (4,9 vs. 6,4º; p < 0,0001). Quinze pacientes (18,2%) foram a óbito durante acompanhamento, oito (53%) eram idosos. Óbito foi associado à idade (62,6 vs. 50,2 anos, p = 0,012), PhA pós-HD (4,8 vs. 6,2º; p = 0,0001), e AEC/ACT pós-HD (0,50 vs. 0,45, p = 0,015). A análise da curva ROC para prever mortalidade constatou que AEC/ACT ≥ 0,47 e PhA ≤ 5,5º apresentam melhor sensibilidade e especificidade. Sobrevida do paciente em um ano foi menor com AEC/ACT pós-HD ≥ 0,47 (69,5% vs. 90,6%; p = 0,019), idade ≥ 65 anos (64,2% vs. 86,2%; p = 0,029), e PhA ≤ 5,5º (68,2 vs. 91,0%; p = 0,002). A análise de regressão de Cox demonstrou que PhA [HR 5,04 (IC 95% 1,60–15,86); p = 0,006] permaneceu associado ao óbito após ajuste para idade e AEC/ACT. Conclusão: BIA é útil ao avaliar distribuição de volume e nutrição em pacientes em HD, e juntamente com julgamento clínico, pode ajudar a determinar o peso seco, principalmente em pacientes idosos. PhA mais estreito e maior AEC/ACT pós-HD foram associados a pior sobrevida em um ano.

Association of Bradycardia and Asystole Episodes with Dialytic Parameters: An Analysis of the Monitoring in Dialysis (MiD) Study

Background

Bradycardia and asystole events are common among patients treated with maintenance hemodialysis. However, triggers of these events in patients on maintenance hemodialysis (HD), particularly during the long interdialytic period when these events cluster, are uncertain.

Methods

The Monitoring in Dialysis Study (MiD) enrolled 66 patients on maintenance HD who were implanted with loop recorders and followed for 6 months. We analyzed associations of predialysis laboratory values with clinically significant bradyarrhythmia or asystole (CSBA) during the 12 hours before an HD session. Associations with CSBA were analyzed with mixed-effect models. Adjusted negative binomial mixed-effect regression was used to estimate incidence rate ratios (IRR) for CSBA. We additionally evaluated associations of CSBA at any time during follow-up with time-averaged dialytic and laboratory parameters and associations of peridialytic parameters with occurrence of CSBA from the start of one HD session to the beginning of the next.

Results

There were 551 CSBA that occurred in the last 12 hours of the interdialytic interval preceding 100 HD sessions in 12% of patients and 1475 CSBA events in 23% of patients overall. We did not identify significant associations between dialytic parameters or serum electrolytes and CSBA in the last 12 hours of the interdialytic interval in adjusted analyses. Median time-averaged ultrafiltration rate was significantly higher in individuals without CSBA (9.8 versus 8, P=0.04). Use of dialysate sodium concentrations ≤135 (versus 140) mEq/L was associated with a reduced risk of CSBA from the start of one session to the beginning of next.

Conclusions

Although a few factors had modest associations with CSBA in some analyses, we did not identify any robust associations of modifiable parameters with CSBA in the MiD Study. Further investigation is needed to understand the high rates of arrhythmia in the hemodialysis population.

Intradialytic hypotension prediction using covariance matrix-driven whale optimizer with orthogonal structure-assisted extreme learning machine

Intradialytic hypotension (IDH) is an adverse event occurred during hemodialysis (HD) sessions with high morbidity and mortality. The key to preventing IDH is predicting its pre-dialysis and administering a proper ultrafiltration prescription. For this purpose, this paper builds a prediction model (bCOWOA-KELM) to predict IDH using indices of blood routine tests. In the study, the orthogonal learning mechanism is applied to the first half of the WOA to improve the search speed and accuracy. The covariance matrix is applied to the second half of the WOA to enhance the ability to get out of local optimum and convergence accuracy. Combining the above two improvement methods, this paper proposes a novel improvement variant (COWOA) for the first time. More, the core of bCOWOA-KELM is that the binary COWOA is utilized to improve the performance of the KELM. In order to verify the comprehensive performance of the study, the paper sets four types of comparison experiments for COWOA based on 30 benchmark functions and a series of prediction experiments for bCOWOA-KELM based on six public datasets and the HD dataset. Finally, the results of the experiments are analyzed separately in this paper. The results of the comparison experiments prove fully that the COWOA is superior to other famous methods. More importantly, the bCOWOA performs better than its peers in feature selection and its accuracy is 92.41%. In addition, bCOWOA improves the accuracy by 0.32% over the second-ranked bSCA and by 3.63% over the worst-ranked bGWO. Therefore, the proposed model can be used for IDH prediction with future applications.

Fluid Overload and Tissue Sodium Accumulation as Main Drivers of Protein Energy Malnutrition in Dialysis Patients

Protein energy malnutrition is recognized as a leading cause of morbidity and mortality in dialysis patients. Protein-energy-wasting process is observed in about 45% of the dialysis population using common biomarkers worldwide. Although several factors are implicated in protein energy wasting, inflammation and oxidative stress mechanisms play a central role in this pathogenic process. In this in-depth review, we analyzed the implication of sodium and water accumulation, as well as the role of fluid overload and fluid management, as major contributors to protein-energy-wasting process. Fluid overload and fluid depletion mimic a tide up and down phenomenon that contributes to inducing hypercatabolism and stimulates oxidation phosphorylation mechanisms at the cellular level in particular muscles. This endogenous metabolic water production may contribute to hyponatremia. In addition, salt tissue accumulation likely contributes to hypercatabolic state through locally inflammatory and immune-mediated mechanisms but also contributes to the perturbation of hormone receptors (i.e., insulin or growth hormone resistance). It is time to act more precisely on sodium and fluid imbalance to mitigate both nutritional and cardiovascular risks. Personalized management of sodium and fluid, using available tools including sodium management tool, has the potential to more adequately restore sodium and water homeostasis and to improve nutritional status and outcomes of dialysis patients.

Artificial intelligence and digital health for volume maintenance in hemodialysis patients

Chronic fluid overload is associated with morbidity and mortality in hemodialysis patients. Optimizing the diagnosis and treatment of fluid overload remains a priority for the nephrology community. Although current methods of assessing fluid status, such as bioimpedance and lung ultrasound, have prognostic and diagnostic value, no single system or technique can be used to maintain euvolemia. The difficulty in maintaining and assessing fluid status led to a publication by the Kidney Health Initiative in 2019 aimed at fostering innovation in fluid management therapies. This review article focuses on the current limitations in our assessment of extracellular volume, and the novel technology and methods that can create a new paradigm for fluid management. The cardiology community has published research on multiparametric wearable devices that can create individualized predictions for heart failure events. In the future, similar wearable technology may be capable of tracking fluid changes during the interdialytic period and enabling behavioral change. Machine learning methods have shown promise in the prediction of volume-related adverse events. Similar methods can be leveraged to create accurate, automated predictions of dry weight that can potentially be used to guide ultrafiltration targets and interdialytic weight gain goals.

Intérêts et limites de l’Hémodialyse Longue Nocturne

L’hémodialyse (HD) Longue Nocturne (HDLN) intermittente permet de combiner dialyse et sommeil. Ses avantages cliniques sont une vitesse d’ultrafiltration réduite, un meilleur contrôle de la volémie avec amélioration de la tolérance des séances et des performances cardiaques, une phosphatémie et des moyennes molécules mieux épurées et une meilleure survie dans les études de cohortes. La qualité de vie n’est pas altérée par la longueur des séances et elle s’améliore quand elle n’est pas optimale lors du transfert de l’HD standard vers l’HDLN. La qualité du sommeil n’est parfois perturbée mais elle n’est pas une cause importante de sortie du programme. La pérennité d’un programme d’HDLN passe par les volontés conjointes médicales et managériales, la sélection des patients stables, le respect des horaires et de la durée de séances, indispensable à la dialyse de sommeil. Les autorités de santé doivent jouer un rôle pour permettre cette modalité dans des conditions financières acceptables. L’information au patient de l’existence de l’HDLN avant le stade de la dialyse est essentielle, aidée par le témoignage des pairs. Les sociétés savantes doivent soutenir la recherche et l’information aux néphrologues. Enfin les conditions architecturales favorisant l’intimité et le sommeil sont une clé de réussite du programme.

Dialysis recovery time: associated factors and its association with quality of life of hemodialysis patients

Introduction

Post-dialysis fatigue is a common and distressing complaint in patients on hemodialysis (HD). The dialysis recovery time (DRT) is a recent and reliable method of Post-dialysis fatigue assessment. We aimed to identify factors affecting the DRT and its relation with HD patients’ quality of life.

Material and methods

This is a cross-sectional study carried out on end-stage renal disease patients on regular HD. All participants underwent detailed history taking and complete physical examination, and data on dialysis and laboratory investigations were also collected. Patients were asked “How long does it take you to recover from a dialysis session?” to calculate the DRT. We used the Malnutrition-Inflammation Score (MIS) and KDQOL-36 questionnaire to assess patients’ nutritional status and quality of life, respectively.

Results

Two hundred and ten patients were screened and 191, with a median age of 47 years, completed the study. Patients had a median DRT of 300 minutes (range: 0.0–2880.0), with 55% of patients reporting a DRT of > 240 minutes and 22.5% of them reporting a DRT of < 30 minutes. Patients had a median MIS score of 7 (range: 0–17). There was a statistically significant negative relation between the DRT and symptom/ problem list (p < 0.001), effects of kidney disease (p < 0.001), burden of kidney disease (p < 0.001), SF-12 physical composite (p = 0.001), and SF-12 mental composite (p < 0.001) of KDQOL. The results of multivariate analyses showed that dialysate Na (p = 0.003), and the number of missed sessions (p < 0.001) were independently correlated with the DRT.

Conclusions

Decreased dialysate Na, and increased number of missed sessions were predictors of prolonged DRT. Patients with prolonged DRT were associated with poorer quality of life. Further randomized clinical trials are needed to assess strategies to minimize the DRT and, perhaps, enhance clinical outcomes.

Trials registration

ClinicalTrials.gov Identifier: NCT04727281. First registration date: 27/01/2021.

A first proof-of-concept for the non-invasive, time-efficient measurement of the plasma sodium concentration for individualized dialysis

Dialysis-induced changes in plasma sodium concentration may cause undesirable side effects. To prevent these, the sodium content in dialysis fluid has to be individualized based on the patient's plasma sodium concentration. In this paper, we describe a simple conductivity based method for measuring the plasma sodium concentration. The method is based on performing a bypass during which the residual volume on the dialysate side of the dialyzer at least partially adopts the sodium concentration on the blood side. The conductivity at dialysate outlet of the dialyzer after the end of bypass corresponds to the sodium concentration. We show that already 14 s of bypass are sufficient to subsequently measure a conductivity that correlates with the blood-side sodium concentration. Thus, the short bypass method allows a time saving of 88% compared to the long bypass of 120 s. In vitro experiments with bovine blood show that plasma sodium concentration can be non-invasively and time-efficiently measured during dialysis. Bland Altman analysis reveals a bias of 0.28 mmol/l and limits of agreement of -3.17 and 3.74 mmol/l for the long bypass. For the short bypass, bias is 0.09 mmol/l and limits are -3.90 and 4.08 mmol/l. Since the method presented is based on established conductivity cells, no additional sensors are required, so that the method could be easily implemented in dialysis machines. In future, performing a bypass at the beginning of a treatment may be used to adjust the composition of dialysis fluid individually for each patient.

The interstitial compartment as a therapeutic target in heart failure

Congestion is the single most important contributor to heart failure (HF) decompensation. Most of the excess volume in patients with HF resides in the interstitial compartment. Inadequate decongestion implies persistent interstitial congestion and is associated with worse outcomes. Therefore, effective interstitial decongestion represents an unmet need to improve quality of life and reduce clinical events. The key processes that underlie incomplete interstitial decongestion are often ignored. In this review, we provide a summary of the pathophysiology of the interstitial compartment in HF and the factors governing the movement of fluids between the interstitial and vascular compartments. Disruption of the extracellular matrix compaction occurs with edema, such that the interstitium becomes highly compliant, and large changes in volume marginally increase interstitial pressure and allow progressive capillary filtration into the interstitium. Augmentation of lymph flow is required to prevent interstitial edema, and the lymphatic system can increase fluid removal by at least 10-fold. In HF, lymphatic remodeling can become insufficient or maladaptive such that the capacity of the lymphatic system to remove fluid from the interstitium is exceeded. Increased central venous pressure at the site of the thoracic duct outlet also impairs lymphatic drainage. Owing to the kinetics of extracellular fluid, microvascular absorption tends to be transient (as determined by the revised Starling equation). Therefore, effective interstitial decongestion with adequate transcapillary plasma refill requires a substantial reduction in plasma volume and capillary pressure that are prolonged and sustained, which is not always achieved in clinical practice. The critical importance of the interstitium in the congestive state underscores the need to directly decongest the interstitial compartment without relying on the lowering of intracapillary pressure with diuretics. This unmet need may be addressed by novel device therapies in the near future.