Brain natriuretic peptide: the reason of respiratory distress is heart disease or lung disease?

N-Terminal Pro-B-Type Natriuretic Peptide as a Marker of Severity of Heart Failure in Children with Congenital Heart Diseases

N-terminal pro-B-type natriuretic peptide (NT-proBNP) has been used as a tool for diagnosis, severity assessment and prognostication of congestive heart failure (CHF) in adults, with specific cut off values for diagnosis and denoting points of intervention. However, there is scarcity of paediatric literature regarding role of NT-proBNP as a marker of heart failure severity and prognostication. So, this study was done to assess the utility of NT-proBNP as a marker of severity of heart failure in children with congenital heart diseases. Single centre, prospective observational study. Children (1 month to 5 years), with congenital heart disease, admitted in the paediatric wards with varying severity of CHF were enrolled. Heart failure severity grading was done according to Laer modification of Ross Classification at the time of presentation to hospital and children were classified as having no/grade I CHF (score: 0-2); mild/grade II CHF (score 3-6); moderate/grade III CHF (score 7-9) or severe/grade IV CHF (score 10-12). NT-proBNP levels were measured within 24 h of admission. Eighty children with congenital heart disease were enrolled in this study. As per modified Ross Classification, 11 had grade I/No heart failure (13.7%), 32 children had grade II/mild heart failure (40%), 36 had grade III/moderate heart failure (45%) and only 1 had grade IV/severe heart failure (1.25%). The median NT-proBNP levels (IQR) in the above mentioned grades of heart failure were found to be 321.11 (211.1-411.78 pg/ml), 750.62 (474.62-995.2 pg/ml), 4159.61 (1440.59-11,857 pg/ml) and 11,320.34 pg/ml, respectively. Seven children (8.75%) expired. Median NT-proBNP value in seven children who died was significantly higher than those who survived [median (IQR): 11,681.01 pg/ml (10,092.72-14,754 pg/ml) vs 839.4 pg/ml (456.67-3288.09 pg/ml), p value < 0.001]. NT-proBNP level of 520.2 pg/ml predicted grade II (mild heart failure) or more severe grades of heart failure with Sensitivity, Specificity, Negative Predictive Value and Positive Predictive Value of 83%, 91%, 57.1% and 98%, respectively. NT-proBNP levels increase progressively with increasing severity of CHF and can be used as a marker of severity of heart failure in children with congenital heart disease presenting with CHF.

Cardiac function in bronchiolitis: Not only a right ventricle matter

OBJECTIVES

Extrapulmonary manifestations of bronchiolitis have been previously studied, with some identifying right ventricle (RV) diastolic/systolic dysfunction. We hypothesized that severe cases of bronchiolitis would have cardiac dysfunction resulting an increase in N-terminal pro-hormone B-type natriuretic peptide (NT-proBNP) values and worse outcomes. Therefore, the objective was to evaluate the existence of cardiac dysfunction and to determine its association with severe bronchiolitis.

METHODS

This prospective cohort study included children hospitalized for bronchiolitis under 1-year old between January 2019 and March 2020. At admission, an echocardiography was performed and plasma levels of NT-proBNP were measured. To analyze outcomes, the cohort was divided into two groups based on the need for positive pressure respiratory support (PPRS), and both were compared to healthy infants.

STATISTICS

bivariant analysis, significant differences p < 0.05.

RESULTS

One hundred eighty-one patients were included; median age was 2 months. Seventy-three patients required PPRS. Compared to controls, patients requiring PPRS showed worse RV systolic function, with lower tricuspid annular-plane systolic excursion (p = 0.002) and parameters of worse right and left diastolic function (trans-tricuspid E and A wave [p = 0.004 and p = 0.04, respectively] and tricuspid tissue doppler imaging [TDI] e' [p = 0.003], trans-mitral E and mitral TDI a' [p = 0.02 and p = 0.005, respectively]). An NT-ProBNP greater than 3582 pg/dl predicts the need for longer necessity of PPRS in patients younger than 2 months.

CONCLUSIONS

In addition to the expected RV systolic dysfunction, patients with severe bronchiolitis have parameters of global diastolic worse function possibly secondary to intrinsic myocardial involvement. NT-ProBNP values at admission had strong discriminatory power to predict worse outcomes.

How to use N-terminal pro-brain natriuretic peptide (NT-proBNP) in assessing disease severity in bronchiolitis

Bronchiolitis is a common viral illness which can lead to severe respiratory compromise and can coexist with or mask cardiac failure. Brain natriuretic peptide (BNP) and the inactive portion of its pro-hormone: N-terminal pro-BNP (NT-proBNP) are excreted in response to cardiomyocyte stretching and are established biomarkers in cardiac failure. Here, we discuss the technicalities of NT-proBNP testing and review available evidence regarding NT-proBNP testing in bronchiolitis. We identified and appraised seven studies assessing the role of BNP or NT-proBNP as biomarkers of bronchiolitis severity, in children with and without underlying congenital cardiac disease. One study of 76 children with dyspnoea showed that the median NT-proBNP level in children with cardiac failure was 7321 pg/mL vs 241 pg/mL in children with a respiratory cause of dyspnoea vs 87.21 pg/mL in healthy controls (p<0.05). A cut-off of 726 pg/mL could aid differentiation between cardiac and respiratory causes of respiratory distress. Other evidence showed a positive correlation between BNP levels and bronchiolitis severity, and that raised BNP can predict acute heart failure in children with congenital cardiac disease presenting with bronchiolitis. However, most studies consisted of small cohorts with conflicting evidence between them. Furthermore, several studies assessed BNP rather than NT-proBNP directly. BNP has a shorter half-life, which may affect analysis. In conclusion, NT-proBNP is a rapid and inexpensive test with the potential to be a useful biomarker in severe bronchiolitis and cases complicated by acute cardiac failure. However, studies with larger cohorts are required to better establish this role.

Insights to correlations and discrepancies between impaired lung function and heart failure in Eisenmenger patients

Impaired lung function and spirometric signs of airway obstruction without common risk factors for chronic obstructive pulmonary disease could be found in patients with Eisenmenger syndrome. This study aimed to analyse the association between lung function parameters and disease severity (including heart failure markers, associated congenital heart defect) as well as the possible reasons for airflow obstruction in Eisenmenger syndrome. The data of 25 patients with Eisenmenger syndrome were retrospectively evaluated. The patients were divided into groups according to airflow obstruction and a type of congenital heart defect. Airflow obstruction was found in nearly third (32%) of our cases and was associated with older age and worse survival. No relation was found between airway obstruction, B-type natriuretic peptide level, complexity of congenital heart defect and bronchial compression. Most of the patients (88%) had gas diffusion abnormalities. A weak negative correlation was noticed between gas diffusion (diffusing capacity of the lung for carbon monoxide) and B-type natriuretic peptide level (r = −0.437, p = 0.033). Increased residual volume was associated with higher mortality (p = 0.047 and p = 0.021, respectively). A link between B-type natriuretic peptide and lung diffusion, but not airway obstruction, was found. Further research and larger multicentre studies are needed to evaluate the importance of pulmonary function parameters and mechanisms of airflow obstruction in Eisenmenger syndrome.

Mechanical ventilation strategies alter cardiovascular biomarkers in an infant rat model

Mechanical ventilation (MV) is routinely used in pediatric general anesthesia and critical care, but may adversely affect the cardiocirculatory system. Biomarkers are increasingly measured to assess cardiovascular status and improve clinical treatment decision-making. As the impact of mechanical ventilation strategies on cardiovascular biomarkers in ventilated infants is largely unknown, we conducted this retrospective study in a healthy in vivo infant rat ventilation model using 14-days old Wistar rats. We hypothesized that 2 h of mechanical ventilation with high and low positive end-expiratory pressure (PEEP), hyperoxemia, hypoxemia, hypercapnia, and hypocapnia would significantly impact B-type natriuretic peptide (BNP), vascular endothelial growth factor (VEGF), and endothelin-1 (ET-1). We found BNP to be driven by both high (9 cmH₂ O) and low (1 cmH₂ O) PEEP compared to ventilated control animals (P < 0.05). VEGF concentrations were associated with high PEEP, hyperoxemia, hypoxemia, and hypocapnia (P < 0.05), whereas ET-1 levels were changed only in response to hypoxemia (P < 0.05). In conclusion, the mode of mechanical ventilation alters plasma biomarker concentrations. Moreover, BNP and VEGF might serve as surrogate parameters for ventilation induced cardiovascular compromise and lung tissue damage. Furthermore, our data support the hypothesis, that sudden onset of hyperoxemia may trigger a quick VEGF release as a possible cellular survival reflex.