Plasma BNP, a useful marker of fluid overload in hospitalized hemodialysis patients

Higher N-terminal pro-brain natriuretic peptide level at onset of peritoneal dialysis-related peritonitis is a risk factor for technique failure

BACKGROUND

Recent studies have suggested that the N-terminal fragment of B-type natriuretic peptide (NT-proBNP) level serve as a significant risk factor for mortality in patients with end-stage renal disease. However, the relationship between NT-proBNP levels and technique failure in peritoneal dialysis-associated peritonitis (PDAP) remains unclear. This study investigated the relationship between NT-proBNP levels at the onset of PDAP and the risk of technique failure in patients with PDAP.

METHODS

A retrospective analysis was conducted on patients with PDAP from December 1, 2009, to December 31, 2021, at our peritoneal dialysis center. We recorded all demographic and baseline clinical data at the time of admission for each PDAP episode. Logistic and Cox regression analyses were performed to assess the association between NT-proBNP levels and technique failure.

RESULTS

Of 485 PDAP episodes included in this study, 130 episodes of technique failure were observed. Multivariate logistic analysis revealed that hospital stay, Na and NT-proBNP levels, and peritoneal dialysate white blood cell counts on days 3 and 5 were independently associated with technique failure. The receiver operating characteristic curve demonstrated that the NT-proBNP level was a better indicator than the other four variables in indicating technique failure. In the multivariate Cox regression analysis, after adjusting for confounding factors, higher NT-proBNP levels (HR of 3.020, 95% CI 1.771, 5.150, P < 0.001) were associated with PDAP technique failure.

CONCLUSIONS

This retrospective study identified the serum NT-proBNP level at the onset of PDAP as an independent risk factor for technique failure in these patients.

Sodium First Approach, to Reset Our Mind for Improving Management of Sodium, Water, Volume and Pressure in Hemodialysis Patients, and to Reduce Cardiovascular Burden and Improve Outcomes

New physiologic findings related to sodium homeostasis and pathophysiologic associations require a new vision for sodium, fluid and blood pressure management in dialysis-dependent chronic kidney disease patients. The traditional dry weight probing approach that has prevailed for many years must be reviewed in light of these findings and enriched by availability of new tools for monitoring and handling sodium and water imbalances. A comprehensive and integrated approach is needed to improve further cardiac health in hemodialysis (HD) patients. Adequate management of sodium, water, volume and hemodynamic control of HD patients relies on a stepwise approach: the first entails assessment and monitoring of fluid status and relies on clinical judgement supported by specific tools that are online embedded in the HD machine or devices used offline; the second consists of acting on correcting fluid imbalance mainly through dialysis prescription (treatment time, active tools embedded on HD machine) but also on guidance related to diet and thirst management; the third consist of fine tuning treatment prescription to patient responses and tolerance with the support of innovative tools such as artificial intelligence and remote pervasive health trackers. It is time to come back to sodium and water imbalance as the root cause of the problem and not to act primarily on their consequences (fluid overload, hypertension) or organ damage (heart; atherosclerosis, brain). We know the problem and have the tools to assess and manage in a more precise way sodium and fluid in HD patients. We strongly call for a sodium first approach to reduce disease burden and improve cardiac health in dialysis-dependent chronic kidney disease patients.

Brain Natriuretic Peptide Is a Marker of Fluid Overload in Incident Hemodialysis Patients

BACKGROUND/AIMS

Brain natriuretic peptide (BNP) is secreted by cardiomyocytes under stretch condition. High blood levels are associated with decreased patient survival in heart failure patients and in hemodialysis (HD) patients. We report the monthly BNP change in the first months of HD therapy in incident patients and its relationship with fluid removal and cardiac history (CH).

METHODS

All patients starting HD therapy in our unit from May 2008 to December 2012 were retrospectively analyzed. Every month (M1 to M6), BNP was assessed before a midweek dialysis session. CH, monthly pre- and postdialysis blood pressure, and postdialysis body weight were collected.

RESULTS

A total of 236 patients were included in the analysis. The median BNP at HD start was 593 (175-1,433) pg/mL, with a significant difference between CH- and CH+ patients (291 vs. 731 pg/mL, p < 0.0001). Mortality was significantly higher in patients in the higher BNP tertile. BNP decreased significantly between M1 and M2 and then plateaued. The BNP change between M1 and M2 and between M1 and M6 was significantly correlated with the initial fluid removal. Applying stepwise multiple regression, the BNP change between M1 and M2 was significantly and independently related to fluid removal. The BNP level at M6 was also related to patient survival.

CONCLUSIONS

We confirm that in incident HD patients, BNP level is related to fluid excess and cardiac status. The BNP decrease in the first months of HD therapy is related to fluid excess correction. BNP appears as an important tool to evaluate hydration status correction after HD onset.

Predialysis NTproBNP predicts magnitude of extracellular volume overload in haemodialysis patients

INTRODUCTION

Increased natriuretic peptides are associated with increased cardiovascular and all-cause mortality for haemodialysis (HD) patients. However, debate continues whether these biomarkers are increased by extracellular water (ECW) excess and can be used to aid clinical assessment of volume status and help determine target weight.

METHODS

We measured N terminal probrain natriuretic peptide (NT-proBNP) predialysis in 375 stable haemodialysis outpatients with corresponding pre and postdialysis multifrequency bioelectrical impedance assessments (MFBIA) of (ECW)/total body water (TBW).

RESULTS

Median age 64 (51-75), 63.9% male, 42.9% diabetic, 43.2% Caucasoid, 14.4% with a history of myocardial infarction, 8.4% coronary artery bypass surgery, dialysis vintage 28.2 (12.3-55.5) months. Median predialysis NT-proBNP 283 (123-989) pmol/l, and predialysis ECW/TBW ratio 0.397 ± 0.029. On multivariate analysis, predialysis log NT-proBNP was associated with predialysis systolic blood pressure (β 0.007, p = 0.000), weight (β -0.008, p = 0.001), valvular heart disease (β 0.342, p = 0.015, ECW/TBW (β 1.3, p = 0.019) and log CRP (β 0.145, p = 0.037). Dividing patients into NTproBNP quartiles, %ECW/TBW and relative ECW overhydration were significantly greater for the highest quartile vs. lowest (40.5 ± 4.1 vs. 39.0 ± 1.1, and 1.51 ± 1.24 vs. 0.61 ± 0.69 l, respectively, p < 0.001).

CONCLUSION

In this study, predialysis NTproBNP values were associated with direct assessments of the extracellular volume excess measured by MFBIA and systolic arterial blood pressure. This suggests that predialysis NTproBNP values can potentially be used to aid clinical assessment of volume status in dialysis patients to determine target weight.

Comparison and Reproducibility of Techniques for Fluid Status Assessment in Chronic Hemodialysis Patients

BACKGROUND

Several methods have been developed to assess the hydration status in chronic hemodialysis (HD) patients. The aim of this study was to compare body bioimpedance spectroscopy (BIS) with ultrasound (US) lung comet score (ULCs), B-type natriuretic peptide (BNP) and inferior vena cava diameter (IVCD) by US for the estimation of dry weight before and after HD and to analyze all methods in terms of fluid status variations induced by HD. An additional aim of this study was to establish the interoperator reproducibility of these methods.

METHODS

Two nephrologists evaluated BIS, ULCs, IVCD during inspiration (min) and expiration (max), the inferior vena cava collapsibility index (IVCCI) as well as BNP before and after HD in 30 patients. The same operators measured BIS, ULCs and IVCD in 28 HD patients in a blinded fashion.

RESULTS

There was a significant reduction in BIS, ULCs, IVCD and BNP after HD (p < 0.001), but a less significant reduction in IVCCI (p = 0.13). There was a significant correlation between BIS and ULCs, BNP and indexed IVCD (IVCDi)min (p < 0.05) before and after HD, and between BIS and IVCDimax only before HD.

CONCLUSION

All methods were able to describe hyperhydration before and after HD, except for IVCCI after HD. All techniques correlated with BIS before HD. After HD, ULCs correlated better with BIS than IVCD in terms of evaluation of fluid status. It could be expected that the ULCs can give a real-time evaluation of interstitial water. The reproducibility of the measurement of BIS, IVCD and ULCs between the two operators was high.

Is there a role for N-terminal probrain-type natriuretic peptide in determining volume status in haemodialysis patients?

BACKGROUND/AIMS

Natriuretic peptides have been reported to be a valuable biomarker for predicting cardiac events and mortality for haemodialysis patients. However, there has been a debate as to whether these biomarkers can be used to assess volume overload and help determine dry weight.

METHODS

We measured the N-terminal probrain natriuretic peptide (NTproBNP) in 366 stable haemodialysis outpatients with a corresponding pre- and post-dialysis multifrequency bioimpedance assessment of extracellular water (ECW)/total body water (TBW).

RESULTS

Median age was 61 years (46-73); 58.5% were male, 28.5% diabetic, and 37.7% Caucasoid; 71.1% had a history of hypertension, 8.4% of myocardial infarction, and 9.3% of coronary artery bypass surgery; dialysis vintage was 54 months (22-85.5), and urea reduction ratio was 73.4 ± 7.6%. Median post-dialysis NTproBNP was 179 pmol/l (68-535), pre-dialysis ECW/TBW was 0.393 ± 0.014, and post-dialysis ECW/TBW was 0.385 ± 0.015. On multivariate analysis log NTproBNP was associated with post-dialysis ECW/TBW (β 9.09, 95% CI 3.22-14.95, p = 0.003), mean arterial pressure (β 0.0087, 95% CI -0.0045 to -0.013, p = 0.000), and ultrafiltration rate (ml/kg · h; β 0.038, 95% CI 0.01-0.06, p = 0.001).

CONCLUSION

In this study postdialysis NTproBNP values were correlated with direct assessments of volume status in haemodialysis patients, i.e. by ECW/TBW, or indirect measures of volume overload, i.e. ultrafiltration rate and post-dialysis mean arterial blood pressure. This suggests that serial NTproBNP values may aid clinical assessments of volume status in dialysis patients.

Volume estimation in dialysis patients: the concordance of brain-type natriuretic peptide measurements and bioimpedance values

Correct estimation of the dialysis patients' hydration status remains an important clinical challenge. Bioimpedance measurements have been validated by various physiological tests, and the use of brain-type natriuretic peptide (BNP) has been validated by inferior vena cava diameter measurements. This is an observational cohort study that evaluated the correspondence between bioimpedance-measured overhydration percentage (OH%) and BNP. We measured predialysis OH% by bioimpedance apparatus (Body Composition Monitor) and BNP by microparticle enzyme-linked immunoassay in 41 prevalent stable hemodialysis patients, 19 (46%) women, aged 58.9 ± 14.5 years. The cohort's average BNP was 2694 ± 3278 pg/mL and 10 (24.4%) of these 41 patients had BNP < 500 pg/mL (average 260.7 ± 108.5). The OH% was 8.5 ± 7.0% among those with a BNP < 500 pg/mL, while the rest of the population had an OH% of 21.4 ± 8.0%, corresponding to excess volumes of 1.6 ± 1.3 and 4.4 ± 3.8 L, respectively. The OH% vs. BNP relationship was best described by the exponential regression of y = 216.4e(0.097x) , predicting a BNP of 216.4 pg/mL at 0% overhydration status (r 0.61). Receiver-operating curves revealed an area under the curve of 0.885 for BNP when the OH% was set ≥15% of overhydration and an area under the curve of 0.918 for OH% when the BNP was set ≥500 pg/mL for being abnormal. We conclude that in our cohort there was a high degree of correspondence between these two tests with an exponential relationship between the measurements.