Relationship of brain natriuretic peptide concentrations to left ventricular function and adverse outcomes in children with end-stage renal disease undergoing hemodialysis

Plasma Brain Natriuretic Peptide Levels in Children with Chronic Kidney Disease and Renal Transplant Recipients: A Single Center Study

Pediatric chronic kidney disease (CKD) patients, as well as kidney transplant patients, are at an increased risk of developing cardiovascular disease. BNP measurement, as a biomarker of cardiovascular risk, has been recommended to this high-risk population. Plasma BNP levels were measured in 56 CKD children in either pre-dialysis stage, hemodialysis (HD) or renal transplant recipients (RTRs) and in 76 sex- and age-matched healthy controls. BNP levels were investigated in HD children, before and after the completion of their HD session. BNP levels in total CKD population, in pre-dialysis stage patients and on HD were significantly higher, compared to the respective controls. HD children had higher BNP levels compared to CKD patients in the pre-dialysis stage. Moreover, post-HD BNP concentration was slightly higher than pre-HD, with the difference being marginally statistically significant. BNP was positively correlated with eGFR, creatinine, cystatin-C and parathormone and negatively with albumin and 25-hydroxyvitamin D. A positive correlation between BNP concentration and the ratio of E/A in pulse-wave Doppler echocardiography was also observed. In conclusion, CKD pediatric patients, mainly those undergoing HD, have high plasma BNP levels which do not decrease after the HD session. This is indicative of a greater risk for future cardiovascular disease.

[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.

Is N-terminal pro-brain natriuretic peptide a reliable marker for body fluid status in children with chronic kidney disease?

INTRODUCTION

Brain natriuretic peptides, released in response to left ventricular stress, have a strong prognostic value in dialysis patients. However, their role in detecting abnormalities of fluid status is under debate; the relationship between volume status and brain natriuretic peptides (BNPs) differs among various studies. The aim of our study was to evaluate the clinical utility of N-terminal proBNP in the assessment of fluid status and cardiovascular risk in this setting.

MATERIAL AND METHODS

The study included 65 children: 10 pre-dialysis, 13 hemodialysis, 12 peritoneal dialysis patients and 30 healthy controls. Volume status was determined by multifrequency bioimpedance and NT-pro-BNP, as well as echocardiography to estimate the left ventricle structure and function.

RESULTS

The median log NT-proBNP values of hemodialysis and peritoneal dialysis patients were 3.66 (2.05-4.90) and 3.57 (2.51-4.13) pg/ml, respectively, and significantly higher compared with the control group (p < 0.001, p < 0.001). On simple correlation, NT-proBNP was correlated with markers of volume overload and cardiac dysfunction. On multivariate regression analysis, only left ventricle mass index (β = 0.402, p = 0.003) and left atrium diameter (β = 0.263, p = 0.018) were independently associated with NT-proBNP (adjusted R 2 of the model: 0.707, p < 0.001).

CONCLUSIONS

Our research suggested that NT-proBNP, which was correlated with LV systolic and diastolic dysfunction and fluid overload as assessed by bioimpedance, can be used to evaluate cardiovascular states in a chronic kidney disease (CKD) population. From the early stages of CKD, periodic monitoring of NT-proBNP levels may be essential for early detection of patients with high risk of cardiovascular events, and for taking preventive intervention as soon as possible.

B-Type Natriuretic Peptide Levels and Cardiac Dysfunction in Children on Peritoneal Dialysis

Background

Abnormalities in left ventricular (LV) structure and function are prevalent in patients on peritoneal dialysis (PD). The risk of cardiovascular mortality is also 10 – 20 times higher in PD patients than in age- and gender-matched healthy control subjects.

Methods

Echocardiography was performed annually or every 6 months for children on PD; the frequency was increased if the patient had hypertension or any heart problem. We retrospectively reviewed echocardiographic findings of these children (since February 2005) by chart review. The linear regression analysis of log(B-type natriuretic peptide, BNP) was performed to evaluate the association between serum BNP and cardiac parameters on echocardiography.

Results

We enrolled 52 patients and evaluated 169 echocardiographic findings in association with serum BNP levels. Systolic blood pressure (adjusted R2 = 0.321), diastolic blood pressure (adjusted R2 = 0.292), LV posterior wall thickness at diastole (0.058), LV posterior wall thickness at systole (0.038), LV internal diameter at diastole (0.177), LV internal diameter at systole (0.132), LV mass index (0.122), thickness of interventricular septum at diastole (0.035), the left atrial (LA) diameter (0.201), LA/aorta diameter ratio (0.113), lateral E/E’ (0.229), and lateral A'/E’ (0.149) showed positive correlation with log(BNP); conversely, LV fractional shortening (FS) (0.065), LV ejection fraction (0.082), right ventricular internal diameter at diastole (0.184), right ventricular fractional shortening (0.754), lateral S’ (0.179), and lateral E’ (0.161) showed negative correlation with log(BNP).

Conclusions

Routine measurement of serum BNP is recommended in children on PD to evaluate the risk of morphological and functional cardiac problems.

Left ventricular dysfunction by conventional and tissue Doppler echocardiography in pediatric hemodialysis patients: relation with plasma brain natriuretic peptide levels

INTRODUCTION

Tissue Doppler imaging (TDI) is a relatively new echocardiography method in children with chronic kidney disease (CKD). The aims of this study were to evaluate left ventricular (LV) diastolic function in pediatric CKD patients using conventional pulsed-wave Doppler echocardiography (cPWD) and TDI methods and correlate them with BNP levels.

MATERIAL AND METHODS

Thirty children on regular hemodialysis (HD) were included. Left ventricular systolic and diastolic indices and BNP levels were measured immediately before and after HD.

RESULTS

After HD, LV and left atrium diameters were significantly decreased (p < 0.001 and p < 0.001, respectively). Transmitral E velocity and E/A ratio decreased (p < 0.001 and p < 0.001, respectively). Also, there were significant decreases in the early diastolic velocity E' of LV wall, septal wall, and anterior wall (p = 0.001, p = 0.004 and p < 0.001, respectively). Mean E/E' ratio and ratios of septal and lateral walls were decreased significantly (p = 0.004, p = 0.002 and p = 0.017, respectively). BNP levels decreased significantly during HD when comparing concentrations before and after HD (p < 0.001). BNP strongly correlated with LV diastolic function indices (before HD: mean E/E' (r = 0.401, p = 0.028), lateral E/E" (r = 0.291, p = 0.025), septal E'(r = -0.398, p = 0.029), lateral wall E' (r = -0.452, p = 0.012) and mean E' (r = -0.469, p = 0.009), after HD: mean E/E' (r = 0.38, p = 0.038) and lateral E/E" (r = 0.474, p = 0.008) and lateral wall E' (r = -0.270, p = 0.037)).

CONCLUSIONS

The cPWD and TDI-derived LV indices are influenced by HD. The diagnostic utility of BNP in the presence of deteriorating renal function may be compromised to some extent.

Determinants and Regression Equations for the Calculation of z Scores of Left Ventricular Tissue Doppler Longitudinal Indexes in a Healthy Italian Pediatric Population

Aim. We investigated the predictors of tissue Doppler left ventricular (LV) longitudinal indexes in a healthy Italian pediatric population and established normative data and regression equations for the calculation of z scores. Methods and Results. A total of 369 healthy subjects aged 1–17 years (age of 6.4 ± 1.1 years, 49.1% female) underwent echocardiography. LV peak longitudinal velocity at systole (s^'), early diastole (e^'), and late diastole (a^') was determined by tissue Doppler. The ratio of peak early diastolic LV filling velocity to e^' was calculated. Age was the only independent determinant of s^' (β = 0.491, p < 0.0001) and the strongest determinant of e^' (β = 0.334, p < 0.0001) and E/e^' (β = −0.369, p < 0.0001). Heart rate was the main determinant of a^' (β = 0.265, p < 0.0001). Male gender showed no effects except for a weak association with lateral s^', suggesting no need of gender-specific reference ranges. Age-specific reference ranges, regression equations, and scatterplots for the calculation of z scores were determined for each index. Conclusion. In a pediatric Italian population, age was the strongest determinant of LV longitudinal dynamics. The availability of age-specific normality data for the calculation of z scores may allow for correctly detecting LV dysfunction in pediatric pathological populations.