Daily dialyses decrease plasma levels of brain natriuretic peptide (BNP), a biomarker of left ventricular dysfunction

Natriuretic Peptides as Predictors of Protein-Energy Wasting in Hemodialysis Population

OBJECTIVE

Imbalance between anabolism and catabolism is linked to cachexia and protein-energy wasting (PEW), especially in frail populations such as patients with chronic kidney disease. PEW is responsible of poor outcomes with increased morbidity and mortality. Several causes are involved in PEW such as insulin resistance, acidosis, or hyperparathyroidism. Natriuretic peptides (NPs) have recently been described as activators of resting energy expenditure through the induction of browning of white adipose tissue in rodents with chronic kidney disease. The present study was therefore implemented to investigate whether NPs could be associated with PEW criteria and predict clinical outcomes.

METHODS

We quantified serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) in a prospective cohort of 231 patients undergoing maintenance hemodialysis and atrial natriuretic peptide in a subgroup of 35 patients. Body composition parameters were measured with bioimpedance spectroscopy.

RESULTS

NT-proBNP was inversely associated with serum albumin, prealbumin, and body mass index and, conversely, positively associated with age and C-reactive protein. NT-proBNP as well as atrial natriuretic peptide were significantly higher in patients with PEW criteria. NT-proBNP was negatively associated with body fat mass. In multiple linear regression, NT-proBNP remained associated with body mass index. Kaplan-Meier analysis revealed a significant correlation between serum NT-proBNP concentrations and all-cause mortality and cardiovascular events. This association remained significant after multivariable Cox regression models adjusted for demographic factors and cardiovascular risk factors.

CONCLUSION

Accumulation of NPs seems to be associated with poor nutritional status and reduced survival among hemodialysis patients. Further studies are needed to confirm this association using resting energy expenditure measurement and adipose tissue biopsy.

Clinical utility of left ventricular strain, wall stress and serum brain natriuretic peptide levels in chronic hemodialysis patients

Background

Left ventricular (LV) global longitudinal strain (GLS) reliably assesses LV systolic function. The precise relation between LV wall stress and serum Brain natriuretic peptide (BNP) concentrations in hemodialysis (HD) patients needs to be clarified. BNP levels are raised in patients with end-stage renal disease (ESRD) and could reflect LV impairment among HD patients.

Aim of this work

This study sought to evaluate the clinical utility of LV-GLS, wall stress and serum BNP levels in chronic HD patients. The correlations between BNP levels with both LV wall stress and LV-GLS were assessed.

Patients and methods

30 ESRD patients on regular HD {categorized into 15 patients with LV ejection fraction (EF) ≤ 50% and 15 patients with LV EF > 50%} and 15-age matched healthy subjects were included. LV function and structure were assessed by conventional echocardiography including LV meridional wall stress (LVMWS), LV mass index (LVMI) and 2-dimensional speckle tracking echocardiography for determination of LV-GLS. Serum BNP levels were evaluated after HD session.

Results

There were significant increase of LVMSW (189.2 ± 81 vs. 72.2 ± 20.6 dynes/cm² × 1000, P < 0.0001), higher levels of BNP (1238 ± 1085.5 vs. 71 ± 23.4 pg/ml, P < 0.0001) while LV-GLS was significantly reduced (15.1 ± 3.1 vs. 20.8 ± 1.7%, P < 0.0001) in HD patients compared to controls. Higher values of LVMWS (246.9 ± 67.5 vs. 131.5 ± 43.6 dynes/cm² × 1000, P < 0.0001) and BNP (1925.4 ± 1087 vs. 550.5 ± 496.5 pg/ml, P < 0.0005) with further impairment of LV-GLS (13.8 ± 2.5 vs. 16.4 ± 5.4%, P < 0.05) were found in patients with LV EF ≤ 50% than those with LV EF > 50%. Serum levels of BNP were positively correlated with LVMI (r = 0.896, P < 0.0001) and LVMWS (r = 0.697, P < 0.0001) but negatively correlated with LV-GLS (r = −0.587, P < 0.0001).

Conclusion

LV-GLS and LVMWS are useful imaging markers for detection of LV dysfunction in HD patients. Serum BNP level is influenced by LV structural abnormalities and suggested to be a crucial hemodynamic biomarker in those patients.

Associations of sensitive cardiac troponin-I with left ventricular morphology, function and prognosis in end-stage renal disease patients with preserved ejection fraction

Sensitive cardiac troponin I (cTnI) predicts all-cause and cardiovascular mortality in various clinical settings. However, its clinical significance in hemodialysis (HD) patients with preserved left ventricular ejection fraction (LVEF) has not been fully elucidated. This study investigated the association of cTnI with LV morphology and function, and its long-term outcome in HD patients with preserved LVEF. This prospective study consists of 96 HD patients with preserved LVEF (69 ± 8 years and 63% male) who underwent two-dimensional echocardiographic examination and biomarker tests including cTnI, brain natriuretic peptide, and high-sensitive C-reactive protein. The primary endpoint was all-cause death and secondary endpoint was cardiovascular death. Factors independently associated with cTnI were systolic blood pressure (β = - 0.239, p = 0.011), heart rate (β = 0.216, p = 0.021), LV mass index (β = 0.231, p = 0.020), and E to e' ratio (β = 0.237, p = 0.016). During a mean follow-up of 3.6 years, primary and secondary endpoints were observed in 23 (24%) and 18 (19%) patients, respectively. In the multivariate Cox proportional hazard analysis, the upper cTnI tertile has significantly increased risk of all-cause mortality [hazard ratio (HR), 2.69; 95% confidence interval (CI), 1.139-6.386; p = 0.024] and that of cardiovascular death (HR, 4.56; 95% CI 2.021-16.968; p = 0.006) independent of echocardiographic measures and other serum biomarkers. In HD patients with preserved LVEF, serum cTnI levels were significantly associated with diastolic function and risk of mortality independent of echocardiographic variables and other biomarkers.

High-Intensity Hemodialysis: The Wave of the Future?

Various modalities of high-intensity hemodialysis are gathering increasing popularity. Some of the advantages of these new dialysis regimens are presented. Time and the increasing use of these novel approaches will ultimately determine their role in the overall management of patients with end-stage renal disease.

Impact of Volume Management on Volume Overload and Rehospitalization in CAPD Patients

Heart failure due to volume overload is a major reason for rehospitalization in continuous ambulatory peritoneal dialysis patients. Strict volume control provides better cardiac functions and blood pressure in this population. Volume management, which is a volume control strategy, may decrease volume overload and related complications. Using a quasi-experimental design, 66 continuous ambulatory peritoneal dialysis patients were randomly assigned to the intervention group ( n = 34) and control group ( n = 32). The patients were followed up for 6 months with scheduled clinic and/or telephone visits; the intervention group adopted volume management strategy, while the control group adopted conventional care. Volume overload and cardiac function were compared between the two groups at the baseline and at 6 months. At Month 6, the intervention group resulted in significant improvement in volume overloaded status, cardiac function, and volume-overload-related rehospitalization. Volume management strategy allows for better control of volume overload and is associated with fewer volume-related readmissions.

Vasoactive Peptide Levels after Change of Dialysis Mode

Background/Aims

Plasma concentrations of the N-terminal fragment of pro-brain natriuretic peptide (NT-proBNP) are increased in end-stage renal disease. Improvement in hemodynamic stability has been reported when switching from hemodialysis (HD) to on-line hemodiafiltration (ol-HDF). The aim of this study was to investigate plasma concentrations of NT-proBNP, BNP and neuropeptide Y (NPY) during a 1-year follow-up, after a change from high-flux HD to postdilution ol-HDF. Additional variables were also studied, e.g. pulse wave velocity and ordinary clinical parameters.

Method

We conducted a prospective, single-center study including 35 patients who were switched from HD to HDF. Plasma concentrations of NT-proBNP, BNP and NPY before and after dialysis were measured at baseline (i.e. HD) and at 1, 2, 4, 6 and 12 months on HDF.

Results

All three peptide levels decreased significantly during HD and HDF when comparing concentrations before and after dialysis. Mean absolute value (before/after) and relative decrease (%) before versus after dialysis was 13.697/9.497 ng/l (31%) for NT-proBNP, 62/40 ng/ml (35%) for BNP and 664/364 pg/l (45%) for NPY. No significant differences were observed when comparing predialysis values over time. However, postdialysis NT-proBNP concentration showed a significant decrease of 48% over time after the switch to HDF.

Conclusion

The postdialysis plasma levels of NT-proBNP, BNP and NPY decreased significantly during both dialysis modes when compared to before dialysis. The postdialysis lowering of NT-proBNP increased further over time after the switch to ol-HDF; the predialysis levels were unchanged, suggesting no effect on its production in the ventricles of the heart.

NT-proBNP and troponin T levels differ after haemodialysis with a low versus high flux membrane

BACKGROUND

Brain natriuretic peptide (BNP), N-terminal-proBNP (NT-proBNP), and high sensitive cardiac troponin T (TnT) are markers that are elevated in chronic kidney disease and correlate with increased risk of mortality. Data are conflicting on the effect of biomarker levels by hemodialysis (HD).Our aim was to clarify to what extent HD with low-flux (LF) versus high-flux (HF) membranes affects the plasma levels of BNP, NT-proBNP, and TnT.

METHODS AND MATERIALS

31 HD patients were included in a crossover design, randomized to start dialysis with a LF-HD or HF-HD dialyzer. Each patient was his/her own control. The dialyses included in the study were the first treatments of two consecutive weeks with each mode of dialysis. Patients normally on hemodiafiltration (HDF) also performed a HDF the third week. Values after HD were corrected for extent of ultrafiltration.

RESULTS

During LF-HD the biomarkers NT-proBNP and TnT increased (15 versus 6%, P ≤ .001) while there was a slight decrease in BNP (P<.05). During HF-HD the NT-proBNP, BNP and TnT levels decreased (P ≤ .01 for all). During HDF all three markers decreased (P<.01 for all). The rise in TnT during LF-HD correlated with dialysis vintage (months on HD, r = .407, P = .026), Kt/V-urea (r = .383, P = .037), HD time in hours/treatment (r = .447, P = .013) and inversely with residual urinary output (r = -.495, P = .005). The baseline levels of BNP and NT-proBNP correlated with blood pressure.

CONCLUSIONS

Cardiac biomarkers increase slightly during LF-HD. A HF-HD eliminates the biomarkers and can mask increases caused by, e.g., myocardial infarction.

Longer interdialytic interval and cause-specific hospitalization in children receiving chronic dialysis

BACKGROUND

Previous studies have demonstrated a relationship between longer interdialytic intervals and hospitalization for cardiovascular causes in adults maintained on hemodialysis (HD). This association has not been previously demonstrated in children. We hypothesized that the risk of hospitalization for hypertension (HTN), fluid overload or electrolyte abnormalities would be increased on the days following a longer interdialytic interval in children.

METHODS

We queried the Pediatric Hospital Information System for all admissions of patients with chronic kidney disease stage V or V-D who received dialysis during the hospitalization. Admissions were divided into two categories: admissions for HTN, fluid overload or electrolyte abnormalities and admissions for all other causes. We assumed that HD patients did not receive dialysis on weekends, and therefore any admission on Monday occurred following a longer interval from the last dialysis. We assumed that all peritoneal dialysis (PD) patients received dialysis on a daily basis. We used mixed effects logistic regression, clustering by patient within each hospital, to assess the increased odds for cause-specific admission on Monday versus other days of the week. We stratified the analysis by dialysis modality, HD or PD.

RESULTS

Among HD patients, the odds ratio of admission for HTN, fluid overload or electrolyte abnormalities was 2.6 (95% CI = 1.4-4.7, P = 0.003) if the admission occurred on a Monday versus other days of the week. The odds of cause-specific admission among PD patients was not significantly different on Monday compared with other days of the week (95% CI =0.5-1.3, P = 0.8).

CONCLUSION

Children receiving chronic HD are more likely to be hospitalized for HTN, fluid overload or electrolyte abnormalities following a longer interdialytic interval. Changes to the frequency of outpatient dialysis treatments may decrease admissions in this population and decrease resource utilization in this high-risk population.

Effect of frequent or extended hemodialysis on cardiovascular parameters: a meta-analysis

BACKGROUND

Increased left ventricular (LV) mass is a risk factor for cardiovascular mortality in patients with chronic kidney failure. More frequent or extended hemodialysis (HD) has been hypothesized to have a beneficial effect on LV mass.

STUDY DESIGN

Meta-analysis.

SETTING & POPULATION

MEDLINE literature search (inception to April 2011), Cochrane Central Register of Controlled Trials and ClinicalTrials.gov using the search terms "short daily HD," "daily HD," "quotidian HD," "frequent HD," "intensive HD," "nocturnal HD," and "home HD."

SELECTION CRITERIA FOR STUDIES

Single-arm cohort studies (with pre- and post-study evaluations) and trials examining the effect of frequent or extended HD on cardiac morphology and function and blood pressure parameters. Studies of hemofiltration, hemodiafiltration, and peritoneal dialysis were excluded.

INTERVENTION

Frequent (2-8 hours, >3 times weekly) or extended (>4 hours, 3 times weekly) HD compared with conventional (≤4 hours, 3 times weekly) HD.

OUTCOMES

Absolute changes in cardiac morphology and function, including LV mass index (LVMI; primary) and blood pressure parameters (secondary).

RESULTS

We identified 38 single-arm studies, 5 crossover trials, and 3 randomized controlled trials. By meta-analysis of 23 study arms, frequent or extended HD significantly reduced LVMI from baseline (-31.2 g/m(2), 95% CI, -39.8 to -22.5; P < 0.001). The 3 randomized trials found a less pronounced net reduction in LVMI (-7.0 g/m(2); 95% CI, -10.2 to -3.7; P < 0.001). LV ejection fraction improved by 6.7% (95% CI, 1.6% to 11.9%; P = 0.01). Other cardiac morphologic parameters showed similar improvements. There also were significant decreases in systolic, diastolic, and mean blood pressure and mean number of antihypertensive medications.

LIMITATIONS

Paucity of randomized controlled trials.

CONCLUSIONS

Conversion from conventional to frequent or extended HD is associated with improvements in cardiac morphology and function, including LVMI and LV ejection fraction, respectively, and several blood pressure parameters, which collectively might confer long-term cardiovascular benefit. Trials with long-term clinical outcomes are needed.

Increasing B-type natriuretic peptide levels predict mortality in unselected haemodialysis patients

AIMS

Cardiac disease is the major cause of death in patients undergoing chronic haemodialysis. Recent studies have found that B-type natriuretic peptide (BNP) levels accurately reflect the cardiovascular burden of dialysis patients. However, the prognostic potential of BNP measurements in dialysis patients remains unknown.

METHODS AND RESULTS

The study included 113 chronic dialysis patients who were prospectively followed up. Levels of BNP were measured at baseline and every 6 months thereafter. The potential of baseline BNP and annual BNP changes to predict all-cause and cardiac mortality were assessed as endpoints. Median follow-up was 735 (354-1459) days; 35 (31%) patients died, 17 (15%) of them from cardiac causes. Baseline BNP levels were similar among survivors and non-survivors, and failed to predict all-cause and cardiac death. Cardiac death was preceded by a marked increase in BNP levels. In survivors BNP levels remained stable [median change: +175% (+20-+384%) vs. -14% (-35-+35%) over the 18 months preceding either death or the end of follow-up, P< 0.001]. Hence, annual BNP changes adequately predicted all-cause and cardiac death in the subsequent year {AUC(all-cause) = 0.70 [SD 0.05, 95% CI (0.60-0.81)]; AUC(cardiac) = 0.82 [SD 0.04, 95%CI (0.73-0.90)]}. A BNP increase of 40% provided the best cut-off level. Cox regression analysis confirmed that annual increases over 40% were associated with a seven-fold increased risk for all-cause and cardiac death.

CONCLUSIONS

Annual BNP increases above 40% predicted all-cause and cardiac death in the subsequent year. Hence, serially measuring BNP levels may present a novel tool for risk stratification and treatment guidance of end-stage renal disease patients on chronic dialysis.

Nightly home hemodialysis: outcome and factors associated with survival

Nightly home hemodialysis (NHHD) has been reported to have a much better survival than the excessive mortality of thrice-weekly in-center dialysis, but the factors influencing survival of NHHD have not been investigated in detail. We studied the association of survival in a 12-year study of 87 NHHD patients from a single center evaluating demographic, sociologic, and anthropomorphic factors, diagnosis, comorbidity, vintage, and dialysis performance and efficiency. Secondly, we compared the survival of the 87 NHHD patients with that reported by the United States Renal Data System (USRDS) using standardized mortality rate (SMR). The average patient age was 52 ± 15 years, and 59% were males, 51% African Americans, and 25% had diabetes. The patients dialyzed 40 ± 6 hours weekly with a stdKt/V of 5.25 ± 0.84. Thirteen patients died. The cumulative survival was 79% at 5 years and 64% at 10 years. Using Cox proportional hazards univariate analysis, 7 of 26 factors studied were associated with mortality: less than high school education, hour of each dialysis, comorbidities, secondary renal disease, congestive heart failure, Leypoldt's eKt/V, and Daugirdas Kt/V. In backward stepwise Cox analysis, education and hour of dialysis were the only factors independently associated with survival. The standardized mortality rate was only 0.30 of that reported by the United States Renal Data System for patients on thrice-weekly hemodialysis adjusted for age, gender, race, and diagnosis. The influence of education was the most significantly associated with survival, and the duration of each dialysis treatment was important. The survival rate of NHHD patients appeared to be superior to intermittent hemodialysis.

Fluid overload correction and cardiac history influence brain natriuretic peptide evolution in incident haemodialysis patients

OBJECTIVES

Brain natriuretic peptide (BNP) is a cardiac peptide secreted by ventricle myocardial cells under stretch constraint. Increased BNP has been shown associated with increased mortality in end-stage renal disease patients. In patients starting haemodialysis (HD), both fluid overload and cardiac history are frequently present and may be responsible for a high BNP plasma level. We report in this study the evolution of BNP levels in incident HD patients, its relationship with fluid removal and cardiac history as well as its prognostic value.

METHODS

Forty-six patients (female/male: 21/25; 68.6 ± 14.5 years old) surviving at least 6 months after HD treatment onset were retrospectively analysed. Plasma BNP (Chemoluminescent Microparticule ImmunoAssay on i8200 Architect Abbott, Paris, France; normal value < 100 pg/mL) was assessed at HD start and during the second quarter of HD treatment (Q2).

RESULTS

At dialysis start, the plasma BNP level was 1041 ± 1178 pg/mL (range: 14-4181 pg/mL). It was correlated with age (P = 0.0017) and was significantly higher in males (P = 0.0017) and in patients with cardiac disease history (P = 0.001). The plasma BNP level at baseline was not related to the mortality risk. At Q2, predialysis systolic blood pressure (BP) decreased from 140.5 ± 24.5 to 129.4 ± 20.6 mmHg (P = 0.0001) and the postdialysis body weight by 7.6 ± 8.4% (P < 0.0001). The BNP level decreased to 631 ± 707 pg/mL (P = 0.01) at Q2. Its variation was significantly correlated with systolic BP decrease (P = 0.006). A high BNP level was found associated with an increased risk of mortality.

CONCLUSIONS

Hence, plasma BNP levels decreased during the first months of HD treatment during the dry weight quest. Whereas initial BNP values were not associated with increased mortality risk, the BNP level at Q2 was independently predictive of mortality. Hence, BNP is a useful tool to follow patient dehydration after dialysis start. Initial fluid overload may act as a confounding factor for its value as a prognostic marker because of cardiac disease.

Hemodialysis-induced cardiac injury: determinants and associated outcomes

BACKGROUND AND OBJECTIVES

Hemodialysis (HD)-induced myocardial stunning driven by ischemia is a recognized complication of HD, which can be ameliorated by HD techniques that improve hemodynamics. In nondialysis patients, repeated ischemia leads to chronic reduction in left ventricular (LV) function. HD may initiate and drive the same process. In this study, we examined the prevalence and associations of HD-induced repetitive myocardial injury and long-term effects on LV function and patient outcomes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Seventy prevalent HD patients were assessed for evidence of subclinical myocardial injury at baseline using serial echocardiography and followed up after 12 mo. Intradialytic blood pressure, hematologic and biochemical samples, and patient demographics were also collected at both time points.

RESULTS

Sixty-four percent of patients had significant myocardial stunning during HD. Age, ultrafiltration volumes, intradialytic hypotension, and cardiac troponin-T (cTnT) levels were independent determinants associated with its presence. Myocardial stunning was associated with increased relative mortality at 12 mo (P = 0.019). Cox regression analysis showed increased hazard of death in patients with myocardial stunning and elevated cTnT than in patients with elevated cTnT alone (P < 0.02). Patients with myocardial stunning who survived 12 mo had significantly lower LV ejection fractions at rest and on HD (P < 0.001).

CONCLUSIONS

HD-induced myocardial stunning is common, and may contribute to the development of heart failure and increased mortality in HD patients. Enhanced understanding of dialysis-induced cardiac injury may provide novel therapeutic targets to reduce currently excessive rates of cardiovascular morbidity and mortality.

Blood B-type natriuretic peptide and dialysis: present assessment and future analyses

Brain natriuretic peptide (BNP) is elevated in hemodialysis (HD) patients and predicts increased mortality. Intra- and interdialytic changes in BNP have not been fully described. End-stage renal disease (ESRD) patients were prospectively recruited at three dialysis centers. At five visits, over a 6-week period, pre- and postdialysis BNP levels were measured. Pre- and postdialysis weights, blood pressure, fluid removed/given and demographic/medical information were recorded. Mean pre- and post-HD BNP (log-transformed) was not significantly different and did not correlate with fluid removed. Both pre- and post-HD BNP significantly decreased across the dialysis week (Pre-HD: intercept = 2.69, slope = -0.097, t = -6.7, P < 0.001) and across the five sessions (slope = -0.046, t = -2.47, P = 0.01). Interdialytic BNP changes are not related to fluid removed. Chronic volume overload and increased left ventricular wall tension likely account for the BNP decrease across dialysis weeks and may be related to higher death rates among HD patients at the beginning of the week.

B-type natriuretic peptides strongly predict mortality in patients who are treated with long-term dialysis

BACKGROUND AND OBJECTIVES

Left ventricular abnormalities contribute to cardiovascular disease in patients with chronic kidney disease and may be detected by measurement of B-type natriuretic peptide in serum.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a prospective cohort study of predialysis patients, patients who were on dialysis, and kidney transplant recipients, serum was collected and assayed for both B-type natriuretic peptide and its N-terminal fragment. Median levels were compared using nonparametric tests, and predictors of B-type natriuretic peptide were determined by linear regression. Survival analysis and Cox regression were performed to examine the association of levels of B-type natriuretic peptide with cardiovascular events and death.

RESULTS

Levels of B-type natriuretic peptide were highest in patients who were on dialysis. Patients who were receiving dialysis and had known cardiovascular disease, were not on the waiting list for kidney transplantation, or had left ventricular systolic dysfunction on echocardiography had significantly higher levels of B-type natriuretic peptide than patients without these characteristics. Glomerular filtration rate was an important predictor of B-type natriuretic peptide levels for patients who were not on dialysis (predialysis and renal transplant recipients). Left ventricular systolic dysfunction predicted B-type natriuretic peptide levels in patients who were on dialysis. Both forms of B-type natriuretic peptide were associated with a two- to three-fold increased risk for death in patients who were on dialysis.

CONCLUSIONS

Levels of B-type natriuretic peptide are greatest in patients who are on dialysis and have cardiovascular comorbidities and are strong predictors of death.