The potential and limitations of plasma BNP measurement in the diagnosis, prognosis, and management of children with heart failure due to congenital cardiac disease: an update

Prognostic role of BNP in children undergoing surgery for congenital heart disease: analysis of prediction models incorporating standard risk factors

BACKGROUND

The routine use of brain natriuretic peptide (BNP) in pediatric cardiac surgery remains controversial. Our aim was to test whether BNP adds information to predict risk in pediatric cardiac surgery.

METHODS

In all, 587 children undergoing cardiac surgery (median age 6.3 months; 1.2-35.9 months) were prospectively enrolled at a single institution. BNP was measured pre-operatively, on every post-operative day in the intensive care unit, and before discharge. The primary outcome was major complications and length ventilator stay >15 days. A first risk prediction model was fitted using Cox proportional hazards model with age, body surface area and Aristotle score as continuous predictors. A second model was built adding cardiopulmonary bypass time and arterial lactate at the end of operation to the first model. Then, peak post-operative log-BNP was added to both models. Analysis to test discrimination, calibration, and reclassification were performed.

RESULTS

BNP increased after surgery (p<0.001), peaking at a mean of 63.7 h (median 36 h, interquartile range 12-84 h) post-operatively and decreased thereafter. The hazard ratios (HR) for peak-BNP were highly significant (first model HR=1.40, p=0.006, second model HR=1.44, p=0.008), and the log-likelihood improved with the addition of BNP at 12 h (p=0.006; p=0.009). The adjunction of peak-BNP significantly improved the area under the ROC curve (first model p<0.001; second model p<0.001). The adjunction of peak-BNP also resulted in a net gain in reclassification proportion (first model NRI=0.089, p<0.001; second model NRI=0.139, p=0.003).

CONCLUSIONS

Our data indicates that BNP may improve the risk prediction in pediatric cardiac surgery, supporting its routine use in this setting.

C-type natriuretic peptide is closely associated to obesity in Caucasian adolescents

CNP is a natural regulator of adipogenesis playing a role in the development of obesity in childhood. Aim of the study was to evaluate CNP plasma levels in normal-weight (N), overweight (OW) and obese adolescents (O). Eighty two subjects (age:12.8±2.4, years) without cardiac dysfunction were enrolled and CNP plasma levels were measured by RIA. NT-proBNP, MR-proANP, AGEs, reactive hyperemia index (RHI) and standard clinical chemistry parameters were also measured. O and OW adolescents had higher values of BMI and fat mass than N. CNP levels were significantly lower in OW:4.79[3.29-21.15] and O:3.81[1.55-13.4] than in N:13.21[7.6-37.8]; p<0.0001N vs O, p=0.0003N vs OW). LogCNP values correlated significantly and inversely with BMI z-score, FM%, TF% and circulating levels of CRP, insulin, total cholesterol, LDL, and triglycerides, in addition to an inverse relationship with skin AGEs and a direct correlation with RHI. LogCNP was also inversely associated with LogNT-proBNP and LogMR-proANP values. Using ROC analysis the risk of obesity resulted significantly (p≪0.0001) associated with CNP values (AUC=0.9724). These results suggest that CNP may play a more important role than BNP and ANP related peptides, as risk marker of obesity, in addition to its involvement in adipogenesis and endothelial dysfunction.

Diagnostic performance and reference values of novel biomarkers of paediatric heart failure

OBJECTIVE

Biomarkers play a pivotal role in heart failure (HF) management. Reference values and insights from studies in adults cannot be extrapolated to the paediatric population due to important differences in pathophysiology and compensatory reserve. We assessed the diagnostic utility of four novel biomarkers in paediatric HF.

METHODS

Midregional (MR) pro-atrial natriuretic peptide (proANP), soluble ST2 (sST2), growth differentiation factor-15 (GDF-15), MR-pro-adrenomedullin (proADM) and N-terminal pro-B natriuretic peptide (NT-proBNP) were measured in 114 patients and 89 controls. HF was defined as the presence of HF symptoms and/or abnormal systolic ventricular function. Receiver-operating characteristics were plotted, and the area under the curve (AUC) was measured. This was repeated for subgroups with cardiomyopathy and congenital heart disease (CHD). Ventricular systolic function was measured by magnetic resonance or echocardiography. Reference values were calculated according to the current guidelines.

RESULTS

The AUC for diagnosing HF was 0.76 for MR-proANP (CI 0.70 to 0.84) and 0.82 for NT-proBNP (CI 0.75 to 0.88). These parameters performed similarly in the subgroups with CHD and cardiomyopathy. By contrast, MR-proADM, GDF-15 and sST2 performed poorly. When used in conjunction with NT-proBNP, no parameter added significantly to its diagnostic accuracy. NT-proBNP, MR-proANP, GDF-15 and sST2 could accurately discriminate between patients with preserved and patients with poor functional status. In a subset of patients with dilated cardiomyopathy, NT-proBNP, MR-proANP, MR-proADM and GDF-15 were associated with poor LV function.

CONCLUSIONS

MR-proANP could accurately detect HF in children and adolescents. Its diagnostic performance was comparable with that of NT-proBNP, regardless of the underlying condition. Reference values are presented.

B-Type Cardiac Natriuretic Peptides in the Neonatal and Pediatric Intensive Care Units

During the last decade, interest in the brain natriuretic peptide (BNP) and N-terminal probrain natriuretic peptide (NT-proBNP) in the pediatric population has progressively increased. The aim of this article is to provide an up to date review of evidences regarding the use of BNP/NT-proBNP in pediatrics, with a particular focus on neonatal intensive care and congenital heart disease. The potentialities of the BNP have been demonstrated in multiple settings, particularly: the screening of congenital/acquired heart disease (CHD) versus pulmonary disease; the evaluation of CHD severity (grade of heart failure, degree of left-to-right shunts); the management of children undergoing cardiac surgery; and monitoring premature infants with patent arterial duct. BNP/NT-proBNP values may be considered an easy and relatively low cost additional diagnostic and prognostic tool. Interpretation of BNP values in children requires attention to important factors, including: laboratory methods, the type of cardiac defect, its severity, and the presence of extracardiac conditions. Of these, the hemodynamic characteristic of CHD and physiologic variations of BNP values occurring during the first weeks of life play a major role. The current evidences in favor of BNP use are mainly derived from single-center, nonrandomized studies, and cost-effectiveness analysis are still lacking. As such, despite sufficient evidences supporting the diagnostic and prognostic potentialities of BNP, these findings should be reinforced by multicenter, randomized studies specifically designed to evaluate outcomes and cost-effectiveness. In addition, standard consensus documents/guidelines, that are currently lacking, are warranted for a more systematic use of BNP in the pediatric age.

Distribution of circulating cardiac biomarkers in healthy children: from birth through adulthood

Aim: While circulating biomarkers are critical tools for cardiovascular adult care, their relevance in childhood is unknown. Methods: We evaluated the behavior of plasma concentrations of clinically relevant cardiac biomarkers (NT-proBNP, hs-cTnI, sST2, Galectin-3) in 106 healthy children. Results: Subjects were divided into age subgroups: 24 newborns (0–30 days), 26 infants (1–12 months), 30 children (1–12 years) and 26 adolescents (13–18 years). Healthy adults were used as control. NT-proBNP (newborns: 504.3 [211.07–942.7] ng/L, median [25–75 percentiles]; infants: 200.64 [76.88–306.73]; children: 97.27 [49.24–271.80]; adolescents: 24.35 [13.14–58.83]; p < 0.001) and hs-cTnI (newborns: 9.3 [3.3–93.8] ng/L; infants: 13.8 [4.82–72.52]; children: 11.45 [4.0–48.10]; adolescents: 2.6[2.07–3.90]; p < 0.001) were highest in the first month of life, showing a decline in the next years. sST2 and Galectin-3 showed no differences. Conclusion: Changes in hs-cTnI and NT-proBNP suggest the design of age- and sex-based reference intervals that will have to be explored in a larger population.

Pediatric Cardiac Intensive Care Society 2014 Consensus Statement: Pharmacotherapies in Cardiac Critical Care Chronic Heart Failure

OBJECTIVE

Heart failure is a serious complication that can occur in patients with a variety of congenital and acquired disorders including congenital heart disease, cardiomyopathy, and myocarditis. Furthermore, heart failure patients comprise an increasing number of ICU admissions. Thus, it is important for those caring for patients with critical cardiovascular disease to have a thorough understanding of the medications used for the treatment of heart failure. The aim of this review is to provide an overview, rationale, indications, and adverse effects of medications used in the treatment of chronic heart failure.

DATA SOURCES

PubMed, Medline, Cochrane Database of Systemic Reviews.

STUDY SELECTION

Studies were selected on their relevance for pediatric heart failure. When limited data on pediatric heart failure were available, studies in adult patients were selected.

DATA EXTRACTION

Relevant findings from studies were selected by the authors.

DATA SYNTHESIS

The rationale for the efficacy of most heart failure medications used in pediatric patients is extrapolated from studies in adult heart failure. Commonly used medications for chronic heart failure include β-receptor antagonists (e.g., carvedilol and metoprolol), and medications aimed at blocking the renin-angiotensin-aldosterone system (e.g., angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, aldosterone receptor antagonists). In addition, diuretics are useful for symptoms of fluid overload. For patients with impaired perfusion, inotropic agents are useful acutely, but may be associated with worse outcomes when used chronically. Newer medications that have been recently approved in adults (e.g., serelaxin, ivabradine, and neprilysin inhibitor [angiotensin receptor blocker]) may prove to be important in pediatric heart failure.

CONCLUSIONS

Heart failure patients are in an important population of critically ill children. The pharmacologic approach to these patients is aimed at treating symptoms of congestion and/or poor perfusion and improving long-term outcomes.

Does N-terminal pro-brain natriuretic peptide correlate with measured shunt fraction in children with septal defects?

BACKGROUND

The aim of this study was to investigate the potential role of N-terminal pro-brain natriuretic peptide in the assessment of shunt severity and invasive haemodynamic parameters in children with atrial septal defects and ventricular septal defects.

METHODS

This is a prospective, controlled (n:62), observational study. Correlation analysis was performed between N-terminal pro-brain natriuretic peptide levels and various invasive haemodynamic measurements in 127 children (ventricular septal defect: 64; atrial septal defect: 63). A ratio of pulmonary to systemic blood flow (Qp/Qs⩾1.5) was considered to indicate a significant shunt.

RESULTS

Statistically significant relationship was found between the mean N-terminal pro-brain natriuretic peptide values of the patients, with Qp/Qs⩾1.5 in both defect types and control group. For ventricular septal defect, N-terminal pro-brain natriuretic peptide level⩾113.5 pg/ml was associated with high specificity and sensitivity for determining the significant shunt. In addition, the cut-off point for determining the significant shunt for atrial septal defect was 57.9 pg/ml. Significant positive correlation was found between all invasive haemodynamic parameters and N-terminal pro-brain natriuretic peptide levels in patients with ventricular septal defects. Whereas significant positive correlation was found only between mean pulmonary artery pressure, right ventricular end-diastolic pressure, and systemic pressure to pulmonary pressure ratio and N-terminal pro-brain natriuretic peptide levels in patients with atrial septal defects.

CONCLUSION

Our study demonstrated that the N-terminal pro-brain natriuretic peptide measurements could be used as a supporting parameter in determining significance of the shunt.

Serum NT-proBNP Levels Are Not Related to Vitamin D Status in Young Patients with Congenital Heart Defects

CONTEXT

Hypovitaminosis D frequently occurs in early life and increases with age. Vitamin D has been suggested to influence cardiac performance and N-terminal-pro-type B natriuretic peptide (NT-proBNP) release in adults with heart failure.

OBJECTIVES

To assess the vitamin D status and the impact of hypovitaminosis D on circulating NT-proBNP levels in young patients with congenital heart defects (CHD).

DESIGN AND PATIENTS

This cross-sectional study included the assessment of serum 25-hydroxyvitamin D (25OHD), parathyroid function markers, and NT-proBNP levels in a series of 230 young in-patients (117 females, 113 males; 6.4 (4.0-9.1) years (median, interquartile range)) with CHD.

RESULTS

Serum 25OHD levels <20 ng/mL were detected in 55.3% of patients. Optimal 25OHD levels (>30 ng/mL) occurred in 25% of patients. Serum 25OHD levels inversely correlated with age (r = -0.169, P = 0.013) and height standard deviation score (r = -0.269, P = 0.001). After correction for age, 25OHD negatively correlated with serum PTH levels (β = -0.200, P = 0.002). PTH levels above the upper quartile (44 pg/mL) occurred in 32% of hypovitaminosis D patients. Serum NT-proBNP levels were not correlated with 25OHD and PTH levels.

CONCLUSIONS

Half of the young CHD patients were diagnosed with 25OHD deficiency and a third of hypovitaminosis D patients experienced hyperparathyroidism. Nonetheless, serum NT-proBNP levels were not associated with hypovitaminosis D as well as hyperparathyroidism.

Biomarkers in paediatric heart failure: is there value?

A biomarker is any measurable, surrogate characteristic, which reflects either the presence or the absence of a disease state. This can be a blood test, an imaging characteristic, an exercise parameter, and even a genetic profile. Serum biomarkers are particularly attractive in that their cost to the patient is relatively low in terms of money, time, risk, and ease of obtaining a sample. The potential benefits of a good biomarker are manifold. This manuscript will review serum biomarkers of proposed utility in paediatric heart failure, especially with respect to their ability to aid clinical decision making, diagnosis, and prognosis.

The Critically Ill Infant with Congenital Heart Disease

This article presents an approach for identification of infants with congenital heart disorders. These disorders are difficult to diagnose because of the complexity and variety of cardiac malformations; additionally presentation can be complicated by age-dependent physiology. By compiling data from the history and the physical examination, the emergency physician can identify lesion category and initiate stabilization procedures. Critical congenital cardiac lesions can be classified as left-sided obstructive ductal dependent, right-sided obstructive ductal dependent, and shunting or mixing. The simplified approach categorizes infants with these lesions respectively as "pink," "blue," or "gray." The emergency provider can provide life-saving stabilization until specialized care can be obtained.

N-Terminal Pro-B Type Natriuretic Peptide as a Marker of Bronchopulmonary Dysplasia or Death in Very Preterm Neonates: A Cohort Study

Background

Bronchopulmonary dysplasia (BPD) is a serious complication of preterm birth. Plasma N-terminal pro-B type natriuretic peptide (NT-proBNP) has been suggested as a marker that may predict BPD within a few days after birth.

Objectives

To investigate the association between NT-proBNP day three and bronchopulmonary dysplasia (BPD) or death and further to assess the impact of patent ductus arteriosus (PDA) on this association in neonates born before 32 gestational weeks.

Methods

A cohort study of 183 neonates born before 32 gestational weeks consecutively admitted to the Neonatal Intensive Care Unit, Aarhus University Hospital, Denmark. On day three plasma samples were collected and echocardiography carried out. NT-proBNP was measured by routine immunoassays. The combined outcome BPD or death was assessed at 36 weeks of postmenstrual age. Receiver operator characteristic (ROC) analysis was performed to determine the discrimination ability of NT-proBNP by the natural log continuous measure to recognize BPD or death. The association of BPD or death was assessed in relation to natural log NT-proBNP levels day three.

Results

The risk of BPD or death increased 1.7-fold with one unit increase of natural log NT-proBNP day three when adjusted for gestational age at birth (OR = 1.7, 95% CI 1.3; 2.3). The association was found both in neonates with and without a PDA. Adjusting for GA, PDA diameter, LA:Ao-ratio, or early onset sepsis did not change the estimate.

Conclusion

We found NT-proBNP to be associated with BPD or death in very preterm neonates. This association was not only explained by the PDA. We speculate that NT-proBNP may help the identification of neonates at risk of BPD as early as postnatal day three.

Changes in Plasma Atrial and Brain Natriuretic Peptide Levels in Children Undergoing Surgical Isolated Atrial Septal Defect Closure

Plasma atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels increase after cardiopulmonary bypass (CPB) in pediatric patients. However, the exact reason for the postoperative increase remains unclear. This study elucidated the perioperative changes in plasma natriuretic peptide levels in children undergoing surgical isolated atrial septal defect (ASD) closure. Between 2010 and 2012, 24 pediatric patients (median 7.1, range 2.7-15.7 years) underwent surgery for simple ASD using CPB under ventricular fibrillation (Group A, 16 patients) or under cardiac arrest (Group B, 8 patients). Natriuretic peptide levels were measured before surgery, on postoperative day 0, 1, 3, and at the first outpatient visit. The pulmonary to systemic blood flow ratio (Qp/Qs) was estimated by echocardiography using an index of right ventricle end-diastolic area. Preoperative natriuretic peptide levels positively correlated with the Qp/Qs. Plasma ANP levels peaked on postoperative day 0, and its values were higher in Group A than in Group B patients (p < 0.001). Plasma BNP levels increased significantly in both Groups on postoperative day 1, and its values were significantly greater in Group A than in Group B patients (p = 0.007). There was a weak negative correlation between the amount of postoperative increase in natriuretic peptide levels and the Qp/Qs. There was no appreciable difference in the acute postoperative clinical course and echocardiographic parameter on postoperative day 3 between Group A and B patients. In conclusion, acute postoperative natriuretic peptide levels after isolated ASD closure were multifactorial, and they might be unreliable for predicting clinical outcomes.

BNP in children with congenital cardiac disease: is there now sufficient evidence for its routine use?

Interest in brain natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) in the management of children with CHD has increased. There are, however, no current guidelines for their routine use. The aim of this review article is to provide an update on the data regarding the use of BNP/NT-proBNP in the evaluation and surgical treatment of children with CHD. BNP/NT-proBNP levels in children with CHD vary substantially according to age, laboratory assay methods, and the specific haemodynamics associated with the individual congenital heart lesion. The accuracy of BNP/NT-proBNP as supplemental markers in the integrated screening, diagnosis, management, and follow-up of CHD has been established. In particular, the use of BNP/NT-proBNP as a prognostic indicator in paediatric cardiac surgery has been widely demonstrated, as well as its role in the subsequent follow-up of surgical patients. Most of the data, however, are derived from single-centre retrospective studies using multivariable analysis; prospective, randomised clinical trials designed to evaluate the clinical utility and cost-effectiveness of routine BNP/NT-proBNP use in CHD are lacking. The results of well-designed, prospective clinical trials should assist in formulating guidelines and expert consensus recommendations for its use in patients with CHD. Finally, the use of new point-of-care testing methods that use less invasive sampling techniques - capillary blood specimens - may contribute to a more widespread use of the BNP assay, especially in neonates and infants, as well as contribute to the development of screening programmes for CHD using this biomarker.

Risk factors of severe hand, foot and mouth disease complicated with cardiopulmonary collapse

BACKGROUND

The aim of this study was to investigate the risk factors for severe hand, foot and mouth disease (HFMD) complicated with cardiopulmonary collapse in children.

METHODS

In total, 176 children aged 6-45 months with severe HFMD from March 2013 to May 2014 were enrolled in the study and divided into two groups, one with cardiopulmonary collapse and the other without. Univariate analysis and multiple logistic regression analysis were used to analyze the risk factors for severe HFMD complicated with cardiopulmonary collapse.

RESULTS

The univariate analysis showed that there was no significant correlation between age, body temperature, consciousness disorders, blood glucose level and severe HFMD complicated with cardiopulmonary collapse. The multiple logistic regression analysis demonstrated that vomiting, circulatory disturbance, enterovirus 71 infection, dysfunction of respiratory rhythm and high level of brain natriuretic peptide were five independent risk factors for severe HFMD complicated with cardiopulmonary collapse.

CONCLUSION

Children with HFMD and the above five risk factors may be at risk for cardiopulmonary collapse and poor prognosis.

Brain Natriuretic Peptide: It's Not About the Brain or Just Another Smart Polypeptide--It's About the Heart

Brain natriuretic peptide (BNP) is a cardiac hormone with diuretic, natriuretic, and vasodilator properties. Measurement of plasma B-type natriuretic peptide concentrations is increasingly used to aid diagnosis, assess prognosis, and tailor treatment in adults with congestive heart failure. Recent studies suggest that the peptide is also useful in pediatric patients. The diagnostic role of plasma BNP in neonates admitted to the NICU has shown promise as an aid in diagnosis in neonates with signs of congenital heart disease; as a biomarker of bronchopulmonary dysplasia, patent ductus arteriosus, and persistent pulmonary hypertension of the newborn; a predictive biomarker of the response to indomethacin in preterm infants; and, more significantly, in acute heart failure.

State of the art of immunoassay methods for B-type natriuretic peptides: An update

The aim of this review article is to give an update on the state of the art of the immunoassay methods for the measurement of B-type natriuretic peptide (BNP) and its related peptides. Using chromatographic procedures, several studies reported an increasing number of circulating peptides related to BNP in human plasma of patients with heart failure. These peptides may have reduced or even no biological activity. Furthermore, other studies have suggested that, using immunoassays that are considered specific for BNP, the precursor of the peptide hormone, proBNP, constitutes a major portion of the peptide measured in plasma of patients with heart failure. Because BNP immunoassay methods show large (up to 50%) systematic differences in values, the use of identical decision values for all immunoassay methods, as suggested by the most recent international guidelines, seems unreasonable. Since proBNP significantly cross-reacts with all commercial immunoassay methods considered specific for BNP, manufacturers should test and clearly declare the degree of cross-reactivity of glycosylated and non-glycosylated proBNP in their BNP immunoassay methods. Clinicians should take into account that there are large systematic differences between methods when they compare results from different laboratories that use different BNP immunoassays. On the other hand, clinical laboratories should take part in external quality assessment (EQA) programs to evaluate the bias of their method in comparison to other BNP methods. Finally, the authors believe that the development of more specific methods for the active peptide, BNP1-32, should reduce the systematic differences between methods and result in better harmonization of results.