Clinical Value of Natriuretic Peptides in Predicting Time to Dialysis in Stage 4 and 5 Chronic Kidney Disease Patients

Changes in Natriuretic Peptide Levels and Subsequent Kidney Function Decline in SPRINT

RATIONALE & OBJECTIVE

Novel approaches to the assessment of kidney disease risk during hypertension treatment are needed because of the uncertainty of how intensive blood pressure (BP) lowering impacts kidney outcomes. We determined whether longitudinal N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurements during hypertension treatment are associated with kidney function decline.

STUDY DESIGN

Prospective observational study.

SETTING & PARTICIPANTS

8,005 SPRINT (Systolic Blood Pressure Intervention Trial) participants with NT-proBNP measurements at baseline and 1 year.

EXPOSURE

1-year change in NT-proBNP categorized as a ≥25% decrease, ≥25% increase, or <25% change (stable).

OUTCOME

Annualized change in estimated glomerular filtration rate (eGFR) and ≥30% decrease in eGFR.

ANALYTICAL APPROACH

Linear mixed-effect and logistic regression models were used to evaluate the association of changes in NT-proBNP with subsequent annualized change in eGFR and ≥30% decrease in eGFR, respectively. Analyses were stratified by baseline chronic kidney disease (CKD) status.

RESULTS

Compared with stable 1-year NT-proBNP levels, a ≥25% decrease in NT-proBNP was associated with a slower decrease in eGFR in participants with CKD (adjusted difference, 1.09%/y; 95% CI, 0.35-1.83) and without CKD (adjusted difference, 0.51%/y; 95% CI, 0.21-0.81; P = 0.4 for interaction). Meanwhile, a ≥25% increase in NT-proBNP in participants with CKD was associated with a faster decrease in eGFR (adjusted difference, -1.04%/y; 95% CI, -1.72 to -0.36) and risk of a ≥30% decrease in eGFR (adjusted odds ratio, 1.44; 95% CI, 1.06-1.96); associations were stronger in participants with CKD than in participants without CKD (P = 0.01 and P < 0.001 for interaction, respectively). Relationships were similar irrespective of the randomized BP arm in SPRINT (P > 0.2 for interactions).

LIMITATIONS

Persons with diabetes and proteinuria >1 g/d were excluded.

CONCLUSIONS

Changes in NT-proBNP during BP treatment are independently associated with subsequent kidney function decline, particularly in people with CKD. Future studies should assess whether routine NT-proBNP measurements may be useful in monitoring kidney risk during hypertension treatment.

PLAIN-LANGUAGE SUMMARY

N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a biomarker in the blood that reflects mechanical stress on the heart. Measuring NT-proBNP may be helpful in assessing the risk of long-term losses of kidney function. In this study, we investigated the association of changes in NT-proBNP with subsequent kidney function among individuals with and without chronic kidney disease. We found that increases in NT-proBNP are associated with a faster rate of decline of kidney function, independent of baseline kidney measures. The associations were more pronounced in individuals with chronic kidney disease. Our results advance the notion of considering NT-proBNP as a dynamic tool for assessing kidney disease risk.

NT-proBNP as predictor of major cardiac events after renal transplantation in patients with preserved left ventricular ejection fraction

BACKGROUND

For the improvement of outcome after renal transplantation it is important to predict future risk of major adverse cardiac events as well as all-cause mortality. We aimed to determine the relationship of pre-transplant NT-proBNP with major adverse cardiac events and all-cause mortality after transplant in patients on the waiting-list with preserved left ventricular ejection fraction.

PATIENTS AND METHODS

We included 176 patients with end-stage renal disease and preserved left ventricular ejection fraction who received a kidney transplant. MACE was defined as myocardial infarction (ST-segment elevation [STEMI] or non-ST-segment elevation [NSTEMI]), stroke or transient ischemic attack), coronary artery disease requiring intervention or bypass or death from cardiovascular causes.

RESULTS

MACE occurred in 28/176 patients. Patients with NT-proBNP levels above 4350 pg/ml had 1- and 5-year survival rates of 90.67% and 68.20%, whereas patients with NT-proBNP levels below 4350 pg/ml had 1- and 5-year survival rates of 100% and 90.48% (p < 0.01). 1- and 5-year MACE-free survival rates were calculated as 78.82% and 74.68% for patients with NT-proBNP > 4350 pg/ml and 93.33% and 91.21% for patients with NT-proBNP < 4350 pg/ml (p < 0.01).

CONCLUSIONS

Pre-transplant NT-proBNP might identify renal transplant candidates at risk for MACE after transplant.

Natriuretic peptide plasma concentrations and risk of cardiovascular versus non-cardiovascular events in heart failure with reduced ejection fraction: Insights from the PARADIGM-HF and ATMOSPHERE trials

BACKGROUND

N-terminal pro-B-type natriuretic peptide (NT-proBNP) plasma concentrations are independent prognostic markers in patients with heart failure and reduced ejection fraction (HFrEF). Whether a differential risk association between NT-proBNP plasma concentrations and risk of cardiovascular (CV) vs non-CV adverse events exists is not well known.

OBJECTIVE

To assess if there is a differential proportional risk of CV vs non-CV adverse events by NT-proBNP plasma concentrations.

METHODS

In this post hoc combined analysis of PARADIGM-HF and ATMOSPHERE trials, proportion of CV vs non-CV mortality and hospitalizations were assessed by NT-proBNP levels (<400, 400-999, 1000-1999, 2000-2999, and >3000 pg/mL) at baseline using Cox regression adjusting for traditional risk factors.

RESULTS

A total of 14,737 patients with mean age of 62 ± 8 years (24% history of atrial fibrillation [AF]) were studied. For CV deaths, the event rates per 1000 patient-years steeply increased from 33.8 in the ≤400 pg/mL group to 142.3 in the ≥3000 pg/mL group, while the non-CV death event rates modestly increased from 9.0 to 22.7, respectively. Proportion of non-CV deaths decreased across the 5 NT-proBNP groups (21.1%, 18.4%, 17.9%, 17.4%, and 13.7% respectively). Similar trend was observed for non-CV hospitalizations (46.4%, 42.6%, 42.9%, 42.0%, and 36.9% respectively). These results remained similar when stratified according to the presence of AF at baseline and prior HF hospitalization within last 12 months.

CONCLUSIONS

The absolute CV event rates per patient years of follow-up were greater and had higher stepwise increases than non-CV event rates across a broad range of NT-proBNP plasma concentrations indicating a differential risk of CV events at varying baseline NT-proBNP values. These results have implications for future design of clinical trials.

N-Terminal Pro-B-Type Natriuretic Peptide and Incident CKD

Introduction

Serum N-terminal pro–B-type natriuretic peptide (NT-proBNP) levels have been associated with the progression of kidney impairment among patients with chronic kidney disease (CKD), but only a few studies have investigated the association between serum NT-proBNP levels and incident CKD in general populations.

Methods

A total of 2486 Japanese community-dwelling residents ≥40 years of age without CKD at baseline were followed up by repeated annual health examinations for 10 years. Participants were divided into 4 groups according to serum NT-proBNP levels. CKD was defined as an estimated glomerular filtration rate (eGFR) <60 ml/min/1.73m² or the presence of proteinuria. Cox proportional hazards models were used to estimate hazard ratios (HRs) for risk of CKD. Linear mixed models were used to compare changes in eGFR.

Results

During the follow-up period, 800 participants developed CKD. The multivariable-adjusted HRs (95% confidence intervals [CIs]) for developing CKD were 1.00 (reference), 1.32 (1.11–1.57), 1.40 (1.10–1.78), and 1.94 (1.38–2.73) for serum NT-proBNP levels of <55, 55–124, 125–299, and ≥300 pg/ml, respectively (P for trend <0.001). The decline of eGFR during the follow-up was significantly more rapid among participants with higher serum NT-proBNP levels (P for trend <0.001). Adding serum NT-proBNP to the model composed of known risk factors for CKD improved the predictive ability for developing CKD.

Conclusions

Higher serum NT-proBNP levels were associated with greater risks of developing CKD and greater decline in eGFR. Serum NT-proBNP could be a useful biomarker for assessing the future risk of CKD in a general Japanese population.

Prognostic Value of N-Terminal Pro-B-Type Natriuretic Peptide and Glomerular Filtration Rate in Patients With Acute Heart Failure

Aims: To investigate the relationship between N-terminal pro-B-type natriuretic peptide (NT-proBNP), Glomerular Filtration Rate (GFR), and outcomes in patients hospitalized with acute heart failure (AHF). Methods: The trial was registered at http://www.chictr.org/cn/. (ChiCTR - ONC - 12001944). A total of 493 patients hospitalized for AHF in cardiology department of the First Affiliated Hospital of Nanjing Medical University from March 2012 to October 2016 were enrolled into registry. The end event was the occurrence of all-cause death within an 18-month follow-up. The data collected from the participants in admission were used to calculate the GFR by chronic kidney disease epidemiology collaboration equation (CKD-EPI) and performed the according statistical analysis. Results: There were 74 participants (13.8%) dropped out and 91 (21.7%) passed away within the 18-month follow up. Comparison of clinical indicators between survival and death group were analyzed for the long-term prognosis of patients with AHF. In the single factor analysis, both NT-proBNP and GFR were statistically significant (P < 0.001). Combined NT-proBNP and GFR in multi-factor COX regression analysis showed significant predictive value (P < 0.001). In receiver operator characteristics (ROC) analyses, the area under the curves (AUC) for NT-proBNP was 0.648 [95%CI: 0.598-0.695, P < 0.001] and for GFR was 0.677 [95%CI: 0.627-0.723, P < 0.001]. According to the Youden index, the best prediction point of NT-proBNP was 2,137 pg/ml and GFR was 61.7 ml/(min·1.73 m2). After using the Binary Logistic Regression to combine the two indicators, the AUC was 0.711, which was significantly compared to the AUC of either single factor. The sensitivity of the combined indicators were 0.535, the specificity were 0.853. According to the cut-off point, these two indexes were separated into four groups for further analysis by Kaplan-Meier survival curve comparison (log-rank test), which showed that patients in the group with higher NT-proBNP and lower GFR had the worst prognosis. Conclusions: In patients with NT-proBNP > 2,137 pg/ml and GFR < 61.7 ml/(min·1.73 m2), the risk of death was significantly higher. The combination of GFR and NT-proBNP improved the predictive value for the long-term prognosis of AHF patients.

Pathophysiology and significance of natriuretic peptides in patients with end-stage kidney disease

Natriuretic peptides (NP), especially B type (BNP) and its N-terminal pro-B type natriuretic peptide (NT-proBNP), have long been regarded as biomarkers of volume overload and tools to exclude heart failure in the general population. However, their role in end-stage kidney disease (ESKD) is less certain given that BNP and NT-proBNP are excreted by the kidney and so serum concentrations of NPs are nearly universally elevated compared to controls. Nevertheless, the accumulated evidence suggests thatserum concentrations of NPs in patients with ESKD show moderate or strong positive relationships with underlying heart disease, abnormal cardiac structure or function and mortality. Limited evidence also supports the role of BNP including NT-proBNP, ANP in some studies, rather than CNP or DNP in risk stratification among ESKD patients as well as the utility of BNP samplings pre- and post- hemodialysis. However, studies of the cut-off values of NPs have yielded inconsistent results, such that further large-scale studies are needed to clarify these issues. This review summarizes the pathophysiology and significance of NPs in ESKD patients, especially their potential role as risk stratification biomarkers in clinical management.

[Natriuretic peptides in dialysis: From theory to clinical practice]

Cardiologists and emergency-wards physicians are used to check natriuretic peptides serum level, mainly B-type natriuretic peptide and N-terminal pro-Brain natriuretic peptide for acute cardiac failure diagnosis. Due to their accumulation in chronic kidney disease and their elimination by dialysis, natriuretic peptides sampling remains debatable in chronic kidney disease patients. In dialysis patients, high natriuretic peptides values are associated with mortality, left ventricular hypertrophy and cardiac failure. However, a single value cannot provide a reliable diagnosis. Our clinical practice is as follows: First, we prefer B-type natriuretic peptide to N-terminal pro-Brain natriuretic peptide because of its shorter half-life, with less impact of renal function and dialysis, making its interpretation easier in case of advanced chronic kidney disease or in dialysis patients; second, we define a reference value of B-type natriuretic peptide at dry weight from serial measurements; third, the B-type natriuretic peptide changes are interpreted according to extracellular fluid and cardiac status, but also from the arteriovenous fistula blood flow. In stable dialysis patients, B-type natriuretic peptide is sampled monthly and weekly in unstable patients. We illustrate our experience using clinical cases of overhydration, new cardiac disease onset, hypovolemia and arteriovenous fistula with high blood flow. Longitudinal follow-up of B-type natriuretic peptide is an important advance in dialysis patients in order to detect and treat extracellular fluid variations and cardiac disease status early, both important factors associated with hard outcomes.

Serum N-terminal Pro-B-type Natriuretic Peptide Predicts Mortality in Cardiac Surgery Patients Receiving Renal Replacement Therapy

Background: N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a useful cardiac biomarker that is associated with acute kidney injury (AKI) and mortality after cardiac surgery. However, its prognostic value in cardiac surgical patients receiving renal replacement therapy (RRT) remains unclear. Objectives: Our study aimed to assess the prognostic value of NT-proBNP in patients with established AKI receiving RRT after cardiac surgery. Methods: A total of 163 cardiac surgical patients with AKI requiring RRT were enrolled in this study. Baseline characteristics, hemodynamic variables at RRT initiation, and NT-proBNP level before surgery, at RRT initiation, and on the first day after RRT were collected. The primary outcome was 28-day mortality after RRT initiation. Results: Serum NT-proBNP levels in non-survivors was markedly higher than survivors before surgery (median: 4,096 [IQR, 962.0-9583.8] vs. 1,339 [IQR, 446-5,173] pg/mL; P < 0.01), at RRT initiation (median: 10,366 [IQR, 5,668-20,646] vs. 3,779 [IQR, 1,799-11,256] pg/mL; P < 0.001), and on the first day after RRT (median: 9,055.0 [IQR, 4,392-24,348] vs. 5,255 [IQR, 2,134-9,175] pg/mL; P < 0.001). The area under the receiver operating characteristic curve of NT-proBNP before surgery, at RRT initiation, and on the first day after RRT for predicting 28-day mortality was 0.64 (95% CI, 0.55-0.73), 0.71 (95% CI, 0.63-0.79), and 0.68 (95% CI, 0.60-0.76), respectively. Consistently, Cox regression revealed that NT-proBNP levels before surgery (HR: 1.27, 95% CI, 1.06-1.52), at RRT initiation (HR: 1.11, 95% CI, 1.06-1.17), and on the first day after RRT (HR: 1.17, 95% CI, 1.11-1.23) were independently associated with 28-day mortality. Conclusions: Serum NT-proBNP was an independent predictor of 28-day mortality in cardiac surgical patients with AKI requiring RRT. The prognostic role of NT-proBNP needs to be confirmed in the future.

The interaction between N-terminal pro-brain natriuretic peptide and fluid status in adverse clinical outcomes of late stages of chronic kidney disease

Introduction

Fluid overload is one of the major characteristics and complications in patients with chronic kidney disease (CKD). N-terminal pro-brain natriuretic peptide (NT-proBNP) is related to fluid status and fluid distribution. The aim of this study is to investigate the interaction between NT-proBNP and fluid status in adverse clinical outcomes of late stages of CKD.

Methods

We enrolled 239 patients with CKD stages 4–5 from January 2011 to December 2011 and followed up until June 2017. Fluid status was presented as hydration status (HS) value measured by body composition monitor, while HS>7% was defined as fluid overload. Clinical outcomes included renal outcomes (commencing dialysis and estimated glomerular filtration rate decline>3 ml/min/1.73 m²/year), all-cause mortality and major adverse cardiovascular events (MACEs).

Results

During a mean follow-up of 3.3±2.0 years, 129(54.7%) patients commenced dialysis, 88(37.3%) patients presented rapid renal function decline, and 48(20.3%) had MACEs or died. All patients were stratified by HS of 7% and the median of plasma NT-proBNP. The adjusted risks for commencing dialysis was significantly higher in patients with high plasma NT-proBNP and HS>7% compared to those with low plasma NT-proBNP and HS≦7%. There was a significant interaction between plasma NT-proBNP and HS in commencing dialysis (P-interaction = 0.047). Besides, patients with high plasma NT-proBNP and HS>7% had greater risks for MACEs or all-cause mortality than others with either high plasma NT-proBNP or HS>7%.

Conclusion

NT-proBNP and fluid overload might have a synergistic association of adverse clinical outcomes in patients with late stages of CKD.

Beneficial Effects of Pentoxifylline Plus Losartan Dual Therapy in Type 2 Diabetes with Nephropathy

BACKGROUND

This study was designed to comparatively assess the effects of add-on pentoxifylline to losartan versus increasing the dose of losartan on serum N-terminal pro-brain natriuretic peptide (NT-proBNP), serum highly sensitive C-reactive protein (hsCRP) and the urinary albumin excretion (UAE) rate in patients with type 2 diabetes and nephropathy.

METHODS

In an open-label, single-center, parallel-group, randomized clinical trial (NCT03006952), 30 patients received b.i.d. dose of pentoxifylline 400mg plus daily dose of losartan 50mg (pentoxifylline arm) and 29 patients received b.i.d. dose of losartan 50mg (losartan arm) during a 12-week follow-up period.

RESULTS

Serum NT-proBNP, serum hsCRP and UAE levels all significantly decreased from baseline in both trial arms. The pentoxifylline and losartan trial arms were equally effective in reducing serum NT-proBNP levels during the course of trial (multivariable adjusted model P value = 0.864, effect size = 0.2%). There was a greater decrease in UAE and serum hsCRP levels in the pentoxifylline arm (P = 0.034, effect size = 7.8%; P = 0.009, effect size = 11.7%, respectively). Conversely, patients in the losartan arm achieved better systolic and diastolic blood pressure control (P < 0.001, effect size = 25.4%; P = 0.010, effect size = 11.3%, respectively).

CONCLUSIONS

Circulating NT-proBNP levels equally and significantly reduced from baseline in the pentoxifylline and losartan treatment arms, in parallel with comparatively superior decreases of UAE and serum hsCRP in the pentoxifylline arm, and larger decreases of systolic and diastolic blood pressures in the losartan arm.