NT-proBNP plasma levels as biomarkers for pulmonary hypertension in healthy infants with respiratory syncytial virus infection

Accuracy of brain natriuretic peptide and N-terminal brain natriuretic peptide for detecting paediatric pulmonary hypertension: a systematic review and meta-analysis

OBJECTIVE

Pulmonary hypertension (PH) is a life-threatening disease, especially in paediatric population. Symptoms of paediatric PH are non-specific. Accurate detection of paediatric PH is helpful for early treatment and mortality reduction. Therefore, we assessed the overall performance of brain natriuretic peptide (BNP) and N-terminal brain natriuretic peptide (NT-proBNP) for diagnosing PH in paediatric population.

METHODS

PubMed, Web of Science, Cochrane Library and Embase databases were screened since their respective inceptions until August 2023. A bivariate random model and a hierarchical summary receiver operating characteristic model were used together to evaluate and summarize the overall performance of BNP and NT-proBNP for diagnosing paediatric PH.

RESULTS

Eighteen studies using BNP/NT-proBNP were assessed, comprising 1127 samples. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and area under the curve (AUROC) of BNP/NT-proBNP were separately as 0.81, 0.87, 6.33, 0.21, 29.50 and 0.91, suggesting a good diagnostic performance of BNP/NT-proBNP for detecting PH in paediatric population. For BNP, the pooled sensitivity, specificity, PLR, NLR, DOR and AUROC were 0.83, 0.89, 7.76, 0.19, 40.90 and 0.93, indicating the diagnostic accuracy of BNP for paediatric PH patients was good. For NT-proBNP, the pooled sensitivity, specificity, PLR, NLR, DOR and AUROC were 0.81, 0.86, 5.59, 0.22, 24.96 and 0.90, showing that NT-proBNP could provide a good value for detecting paediatric PH.

CONCLUSIONS

Both BNP and NT-proBNP are good markers for differentiating paediatric PH patients from non-PH individuals.

Correlation between urinary and serum NT-proBNP in acute bronchiolitis: A pilot study

BACKGROUND AND AIMS

We aimed to analyze the correlation of urinary with serum N-terminal pro-brain natriuretic peptide (NT-proBNP) concentrations and its association with severity in acute bronchiolitis.

MATERIAL AND METHODS

A pilot observational study was conducted between October 1, 2021 and March 31, 2022 including acute bronchiolitis cases who attended our institution. Serum and urinary NT-proBNP concentrations were determined using the Alere i NT-proBNP assay in time-matched urine and blood samples. The Mann-Whitney U test, Spearman's correlations, and simple linear regression were utilized to analyze the association of urine NT-proBNP levels with serum NT-proBNP and with variables indicative of severe bronchiolitis.

RESULTS

Seventeen infants (median age 68 [IQR: 36-91] days) with 36 time-matched samples were included. The urine NT-proBNP was positively and strongly correlated with the serum NT-proBNP concentrations (Spearman's ρ = 0.81 & R2  coefficient = 0.751; p < 0.001), and increased with higher C-reactive protein, (p = 0.004), procalcitonin (p = 0.001), and pCO2 (p = 0.029) levels. The initial urinary NT-proBNP concentrations were higher in those infants that required ventilatory support compared with those without this outcome (1.85 [IQR: 1.16-2.44] vs. 0.63 [IQR: 0.45-0.84] pg/mg); p < 0.001); and resulted positively and strongly correlated with the duration of the ventilatory support (Spearman's ρ = 0.76; p < 0.001) and the length of stay hospitalization (Spearman's ρ = 0.84; p < 0.001).

CONCLUSION

The urinary NT-proBNP concentrations could be a reliable surrogate for serum NT-proBNP levels and resulted elevated in cases of acute bronchiolitis with complicated evolution, suggesting a potential as a noninvasive tool to assess severity in this setting.

Echocardiographic Markers of Mild Pulmonary Hypertension are not Correlated with Worse Respiratory Outcomes in Infants with Bronchiolitis

Pulmonary hypertension has been reported as a crucial factor in the pathophysiology of severe bronchiolitis. The aim of this study was to evaluate pulmonary artery pressure (PAP) in patients with bronchiolitis and to analyze their correlation with clinical outcomes. This prospective cohort study examined children admitted for bronchiolitis. PAP was assessed by right ventricle (RV) acceleration/ejection time ratio (AT/ET), isovolumic relaxation time, eccentricity index, and the presence of a pulmonary systolic notch. Pulmonary hypertension (PH) was considered if at least two altered parameters were present. Severity of clinical course was established by higher N-terminal (NT)-prohormone BNP (NT-proBNP) values, the need for positive pressure respiratory support (PPRS), and the duration of hospital admission. One hundred sixty-nine children were included in analysis. Sixty-eight patients (40%) required PPRS, and those patients had increased NT-proBNP values and worse tricuspid annular systolic excursion (TAPSE) compared to mild cases (p < 0.001and p < 0.001, respectively). Twenty-two (13%) cases had at least two altered parameters of PAP and met criteria for presumed PH, with no differences in NT-proBNP values, TAPSE, need for PPRS or hospital length of stay compared to normal PAP group (p = 0.98, p = 0.07, p = 0.94 and p = 0.64, respectively). We found no correlation between altered RV AT/ET and worse cardiac function, NT-proBNP values or hospital length of stay. In our cohort, the presence of echocardiographic findings of PH were not associated with worse clinical outcomes. Patients with severe bronchiolitis had higher values ​​of NT-proBNP but, interestingly, no clear association with PH.

Routine laboratory test to assess the need of respiratory support in acute bronchiolitis

BACKGROUND AND OBJECTIVES

Accurate and readily available biomarkers to predict the clinical course of bronchiolitis would enable enhanced decision-making in this setting. We explored the relationship of several biochemical parameters available at the pediatric emergency care setting with the need of advanced respiratory support (ARS): continuous positive airway pressure (CPAP), biphasic positive airway pressure (BiPAP), or invasive mechanical ventilation (MV) in bronchiolitis.

METHODS

Single-center, prospective, observational, including infants aged less than 12 months diagnosed with acute bronchiolitis at the Pediatric Emergency Department. Determination of plasmatic values of several laboratory tests was performed at the time of hospital admission. Multivariate logistic analysis identified independent predictors for need of ARS.

RESULTS

From October 1, 2018 to May 1, 2020, we recruited 149 infants (58% males; median age of 1 [0.5-2.5] month). Thirty-seven (25%) cases required ARS. After adjusting by age, bacterial superinfection, and comorbidities in the multivariate analysis, only higher levels of glycemia (p = 0.001), C-reactive protein (CRP) (p = 0.028), CRP/albumin ratio (p = 0.032), and NT-proBNP (p = 0.001) remained independently associated with ARS. These biomarkers reached moderate prediction accuracy with area under the curve of receiver operator curve curves ranging from 0.701 to 0.830 (p = 0.001). All they presented relatively high specificity (0.75-0.84) and negative predictive values (0.77-0.89) with low sensitivity and positive predictive values. They also correlated significantly with length of stay hospitalization (p = 0.001).

CONCLUSION

Increased plasmatic levels of CRP, CRP/albumin ratio, glycemia, and NT-proBNP at hospital admission are associated with the need for ARS in infants with acute bronchiolitis.

The Significance of The Detection of Serum Lactate Dehydrogenase, Hypersensitive C-Reactive Protein, and N-Terminal Pro-Brain Natriuretic Peptide for the Evaluation of the Severity and Progression of Pediatric Patients with Traumatic Brain Injury

OBJECTIVE

This study aimed to investigate changes in the levels of serum lactate dehydrogenase (LDH), hypersensitive C-reactive protein (hs-CRP), and N-terminal pro-brain natriuretic peptide (NT-proBNP) in pediatric patients with traumatic brain injury and the clinical significance of detecting these changes for the evaluation of injury severity and patient progress.

METHODS

A retrospective study was conducted on 40 pediatric patients admitted to the Tongren Hospital of China Capital Medical University with traumatic brain injury between January 2018 and December 2019. Immunoturbidimetric assay and electrochemiluminescence were used to detect the serum levels of LDH, hs-CRP, and NT-proBNP. Correlation analysis was used to determine the degree of association between the indicators and the sensitivity and specificity of each indicator.

RESULTS

The serum levels of LDH, hs-CRP, and NT-proBNP in the poor-prognosis group were higher than those in the good-prognosis group, and the differences were statistically significant (P < 0.05).

CONCLUSION

The detection of serum LDH, hs-CRP, and NT-proBNP might be of great significance for the evaluation of the severity of a traumatic brain injury, disease progression, and the prognosis of pediatric patients with traumatic brain injury. The combined detection of the relevant indicators could provide more effective sensitivity and specificity and therefore offer better guidance and assistance in clinical practice.

A narrative review of research advances in hypoxic pulmonary hypertension

Background and Objective

Hypoxic pulmonary hypertension (HPH) is a pathological syndrome characterized by pulmonary vasoconstriction and pulmonary vascular remodeling caused by hypoxia, which eventually leads to right heart failure or death. There are 2 stages of onset of HPH: hypoxic pulmonary vasoconstriction (HPV) and hypoxic pulmonary vascular remodeling (HPVR). It is an important pathophysiological link in the pathogenesis of chronic obstructive pulmonary disease (COPD) and chronic mountain sickness (CMS), and its severity is closely related to the course and prognosis of COPD and CMS. However, there is a lack of systematic review on the diagnosis, pathogenesis and treatment of HPH. The objective of this paper is to review the diagnosis, pathogenesis, treatment of HPH.

Methods

In this paper, the method of literature review is adopted to obtain the information about HPH. Based on the literature, comprehensive and systematic review is made. The diagnosis, pathogenesis, treatment of HPH are summarized.

Key Content and Findings

Right heart catheterization is the gold standard for diagnosing HPH. Hypoxia-inducible factor, oxidative stress, metal metabolism, ion channel, inflammatory cytokines, cell apoptosis and vascular factors are the main pathogenesis of HPH. The treatment of HPH includes long-term oxygen therapy, statins, prostaglandins, phosphodiesterase inhibitor and ET receptor antagonists.

Conclusions

Although great progress has been made in the pathophysiology and molecular biology of HPH, it is still unclear which factors play a leading role in the pathogenesis of HPH, and no breakthrough has been made in the treatment of HPH. It is believed that the specific mechanism will be revealed as the research continues, and earlier diagnosis and the development of more effective targeted drugs will be the focus of future research.

Characterization of Cardiopulmonary Interactions and Exploring Their Prognostic Value in Acute Bronchiolitis: A Prospective Cardiopulmonary Ultrasound Study

We aimed to delineate cardiopulmonary interactions in acute bronchiolitis and to evaluate the capacity of a combined cardiopulmonary ultrasonography to predict the need for respiratory support. This was a prospective observational single-center study that includes infants <12 month of age admitted to a hospital due to acute bronchiolitis. All the included patients underwent clinical, laboratory and cardiopulmonary ultrasonographic evaluation at the same time point within 24 h of hospital admission. The existence of significant correlation between cardiac and respiratory parameters was the primary outcome. The association of different cardiopulmonary variables with the need of respiratory support higher than O₂, the length of stay hospitalization, the PICU stay and the duration of respiratory support were a secondary outcome. We enrolled 112 infants (median age 1 (0.5–3) months; 62% males) hospitalized with acute bronchiolitis. Increased values of the pulmonary variables (BROSJOD score, pCO₂ and LUS) showed moderate correlations with NT-proBNP and all echocardiographic parameters indicative of pulmonary hypertension and myocardial dysfunction (Tei index). Up to 36 (32%) infants required respiratory support during the hospitalization. This group presented with higher lung ultrasound score (p < 0.001) and increased values of NT-proBNP (p < 0.001), the Tei index (p < 0.001) and pulmonary artery pressures (p < 0.001). All the analyzed respiratory and cardiac variables showed moderate-to-strong correlations with the LOS of hospitalization and the time of respiratory support. Lung ultrasound and echocardiography showed a moderate-to-strong predictive accuracy for the need of respiratory support in the ROC analysis, with the AUC varying from 0.74 to 0.87. Those cases of bronchiolitis with a worse pulmonary status presented with a more impaired cardiac status. Cardiopulmonary ultrasonography could be a useful tool to easily identify high-risk populations for complicated acute bronchiolitis hospitalization.

Deficiency in ST2 signaling ameliorates RSV-associated pulmonary hypertension

Pulmonary hypertension (PH) observed during respiratory syncytial virus (RSV) bronchiolitis is associated with morbidity and mortality, especially in children with congenital heart disease. Yet, the pathophysiological mechanisms of RSV-associated PH remain unclear. Therefore, this study aimed to investigate the pathophysiological mechanism of RSV-associated PH. We used a translational mouse model of RSV-associated PH, in which wild-type (WT) and suppression of tumorigenicity 2 (ST2) knockout neonatal mice were infected with RSV at 5 days old and reinfected 4 wk later. The development of PH in WT mice following RSV reinfection was evidenced by elevated right ventricle systolic pressure, shortened pulmonary artery acceleration time (PAT), and decreased PAT/ejection time (ET) ratio. It coincided with the augmentation of periostin and IL-13 expression and increased arginase bioactivity by both arginase 1 and 2 as well as induction of nitric oxide synthase (NOS) uncoupling. Absence of ST2 signaling prevented RSV-reinfected mice from developing PH by suppressing NOS uncoupling. In summary, ST2 signaling was involved in the development of RSV-associated PH. ST2 signaling inhibition may be a novel therapeutic target for RSV-associated PH.NEW & NOTEWORTHY We report that the pathogenic role of ST2-mediated type 2 immunity and mechanisms contribute to RSV-associated pulmonary hypertension. Inhibiting ST2 signaling may be a novel therapeutic target for this condition.

Efficacy and safety of riociguat in the treatment of chronic thromboembolic pulmonary arterial hypertension: A meta-analysis

BACKGROUND

Riociguat is a novel soluble guanylate cyclase stimulator, and has been widely used for the treatment of pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension (CTEPH). Some studies found that riociguat had better effects on CTEPH and proved to be safe, but the results were not utterly consistent. Therefore, the purpose of this study was to comprehensively evaluate the efficacy and safety of riociguat in the treatment of CTEPH.

METHODS

Randomized controlled trials on riociguat for the treatment of CTEPH were searched through such electronic databases as PubMed, Embase, Cochrane Library, Web of Science, China national knowledge internet, and Wanfang. The outcomes included exercise capacity, pulmonary hemodynamics, and side effects. The fixed-effects or random-effects models were used to analyze the pooled data, and heterogeneity was assessed by the I2 test.

RESULTS

Four studies involving 520 patients were included in this meta-analysis. Compared with the placebo group, riociguat significantly improved the hemodynamic indexes and increased 6-min walking distance (P < .0001, standardized mean difference (SMD) = -0.24, 95%CI -0.35 to -0.12; P < .00001, SMD = 0.52, 95%CI 0.33 to 0.71), and decreased the Borg dyspnea score (P = .002, SMD = -0.31, 95%CI -0.51 to -0.12). In addition, riociguat could also significantly reduce the living with pulmonary hypertension scores and increase the EQ-5D scores (P = .01, SMD=-0.23, 95%CI -0.42 to -0.05; P < .00001, SMD = 0.47, 95%CI 0.27 to 0.66), but there was no significant difference in the change level of N-terminal pro-hormone B-type natriuretic peptide in patients with riociguat (P = .20, SMD = -0.24, 95%CI -0.61 to -0.13). The common adverse events of riociguat were dyspepsia and peripheral edema, and no other serious adverse reactions were observed.

CONCLUSIONS

We confirmed that riociguat had better therapeutic effects in improving the hemodynamic parameters and exercise capacity in patients with CTEPH without inducing serious adverse events. This will provide a reasonable medication regimen for the treatment of CTEPH.

Early elevated NT-proBNP but not troponin I is associated with severe bronchiolitis in infants

BACKGROUND

We aimed to explore and to compare the association between the NT-proBNP and high-sensitivity troponin I (hs-cTnI) at early stages of acute bronchiolitis with echocardiographic alterations, clinical severity and outcomes.

METHODS

A single centre, prospective observational study including previously healthy infants aged 1-12 months with bronchiolitis admitted to a tertiary hospital from April 2019 to March 2020. All patients underwent clinical, laboratory and echocardiographic evaluation at the same time point within 12 h of hospital admission. NT-proBNP > 1121 pg/ml and hs-cTnI > 26 ng/L were considered elevated. The primary outcome measure was the association of raised cardiac biomarkers with the need for PICU admission.

RESULTS

We enrolled 40 infants with median levels of NT-proBNP of 1176 (520-3030) pg/ml and hs-cTnI of 11.5 (5-21) ng/L at the time of hospital admission. Raised levels of NT-proBNP and hs-cTnI in 50% and 20% of cases, respectively. Of them, 15 (37%) required PICU admission during the hospitalization. Increased NT-proBNP was associated with PICU admission (adjusted OR 9.5 (CI95% 1.4-64); p = 0.020), prolonged hospitalization (β = 2.7; p = 0.012) and duration of oxygen administration (β = 2.7; p = 0.004) in the multivariate analysis. There were no differences in hs-cTnI levels regarding PICU admission (p = 0.866). Increased hs-cTnI levels were only associated with oxygen administration duration (Spearman rho = 0.38; p = 0.017), but this association disappeared in the multivariate analysis. Only NT-proBNP was associated with echocardiographic parameters of myocardial dysfunction (p < 0.001), and pulmonary hypertension (p < 0.001) CONCLUSION: Early elevated NT-proBNP but not hs-cTnI could be used as a biomarker for myocardial strain and disease severity in bronchiolitis.

Cardiovascular impact of COVID-19 with a focus on children: A systematic review

BACKGROUND

Since the beginning of the pandemic, coronavirus disease-2019 (COVID-19) in children has shown milder cases and a better prognosis than adults. Although the respiratory tract is the primary target for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), cardiovascular involvement is emerging as one of the most significant and life-threatening complications of SARS-CoV-2 infection in adults.

AIM

To summarize the current knowledge about the potential cardiovascular involvement in pediatric COVID-19 in order to give a perspective on how to take care of them during the current pandemic emergency.

METHODS

Multiple searches in MEDLINE, PubMed were performed using the search terms "COVID-19" or "SARS-CoV-2" were used in combination with "myocardial injury" or "arrhythmia" or "cardiovascular involvement" or "heart disease" or "congenital heart disease" or "pulmonary hypertension" or "long QT" or "cardiomyopathies" or "channelopathies" or "Multisystem inflammatory system" or "PMIS" or "MIS-C" or "Pediatric multisystem inflammatory syndrome" or "myocarditis" or "thromboembolism to identify articles published in English language from January 1st, 2020 until July 31st, 2020. The websites of World Health Organization, Centers for Disease control and Prevention, and the Johns Hopkins Coronavirus Resource Center were reviewed to provide up to date numbers and infection control recommendations. Reference lists from the articles were reviewed to identify additional pertinent articles. Retrieved manuscripts concerning the subject were reviewed by the authors, and the data were extracted using a standardized collection tool. Data were subsequently analyzed with descriptive statistics. For Pediatric multisystemic inflammatory syndrome temporally associated with COVID-19 (PMIS), multiple meta-analyses were conducted to summarize the pooled mean proportion of different cardiovascular variables in this population in pseudo-cohorts of observed patients.

RESULTS

A total of 193 articles were included. Most publications used in this review were single case reports, small case series, and observational small-sized studies or literature reviews. The meta-analysis of 16 studies with size > 10 patients and with complete data about cardiovascular involvement in children with PMIS showed that PMIS affects mostly previously healthy school-aged children and adolescents presenting with Kawasaki disease-like features and multiple organ failure with a focus on the heart, accounting for most cases of pediatric COVID-19 mortality. They frequently presented cardiogenic shock (53%), ECG alterations (27%), myocardial dysfunction (52%), and coronary artery dilation (15%). Most cases required PICU admission (75%) and inotropic support (57%), with the rare need for extracorporeal membrane oxygenation (4%). Almost all of these children wholly recovered in a few days, although rare deaths have been reported (2%). Out of PMIS cases we identified 10 articles reporting sporadic cases of myocarditis, pulmonary hypertension and cardiac arrythmias in previously healthy children. We also found another 10 studies reporting patients with pre-existing heart diseases. Most cases consisted in children with severe COVID-19 infection with full recovery after intensive care support, but cases of death were also identified. The management of different cardiac conditions are provided based on current guidelines and expert panel recommendations.

CONCLUSION

There is still scarce data about the role of cardiovascular involvement in COVID-19 in children. Based on our review, children (previously healthy or with pre-existing heart disease) with acute COVID-19 requiring hospital admission should undergo a cardiac workup and close cardiovascular monitoring to identify and treat timely life-threatening cardiac complications.

The Assessment of Myocardial Strain by Cardiac Imaging in Healthy Infants with Acute Bronchiolitis: A Systematic Review and Meta-Analysis

This study aims to systematically review the incidence of myocardial strain detected by echocardiography in previously healthy infants with acute bronchiolitis and its role as a predictor for adverse outcomes in this setting.

METHODS

Pubmed/Medline, Excerpta Medica Data Base (EMBASE), and Cochrane Library were searched in April 2020 to identify original observational prospective studies that systematically performed echocardiography for the screening of myocardial strain in healthy infants with acute bronchiolitis. Pooled estimates were generated using random-effects models. Heterogeneity within studies was assessed using Cochran's Q and I² statistics. Funnel plots and Egger´s regression method were constructed to evaluate publication bias. Sensitivity analyses were also conducted to evaluate potential sources of heterogeneity.

RESULTS

After a detailed screening of 305 articles, a total of 10 studies with 395 participants (mean of 40 participants per study) was included. Five of them were classified as high-quality studies. Up to 28% of cases presented adverse outcomes. The echocardiographic screening for myocardial strain was performed within the first 24 h of admission in 92% cases. Tissue Doppler imaging and Speckle-Tracking echocardiography were performed only in 20% of cases. The presence of pulmonary hypertension was evaluated with methods different from the tricuspid regurgitation jet in 64% of cases. Seven studies found some grade of myocardial strain with a pooled incidence of 21% (CI 95%, 11-31%), in the form of pulmonary hypertension (pooled incidence of 20% (CI 95%, 11-30%)), and myocardial dysfunction (pooled incidence of 5% (CI 95%, 1-9%)). The presence of these echocardiographic alterations was associated with adverse outcomes (pooled relative risk = 16; CI 95%, 8.2-31.5). After a subgroup analysis based on the echocardiographic techniques used, no significant heterogeneity across the studies was observed. There was no evidence of publication bias when assessed by Egger´s test. Cardiac biomarkers to assess myocardial strain were used in five studies. Only N-terminal-pro-brain natriuretic peptide accurately predicted the presence of myocardial strain by echocardiography.

CONCLUSIONS

Myocardial strain is not infrequent in previously healthy infants with acute bronchiolitis, and it could be present at the early stages of the disease with prognostic implications. There is a need for sufficiently powered prospective studies with a similar methodology, preferably employing advanced imaging techniques, to conclusively address the usefulness of the assessment of myocardial strain in this setting.

Left Ventricular Dysfunction and Plasmatic NT-proBNP Are Associated with Adverse Evolution in Respiratory Syncytial Virus Bronchiolitis

AIM

To investigate whether the presence of left ventricular myocardial dysfunction (LVMD) assessed by Tei index (LVTX) impacts the outcomes of healthy infants with Respiratory Syncytial Virus Bronchiolitis (RSVB). To explore whether N-terminal pro-B-type natriuretic peptide (NT-proBNP) increases the accuracy of traditional clinical markers in predicting the outcomes.

METHODS

A single-centre, prospective, cohort study including healthy infants aged 1-12 months old admitted for RSVB between 1 October 2016 and 1 April 2017. All patients underwent clinical, laboratory and echocardiographic evaluation within 24 h of admission. Paediatric intensive care unit (PICU) admission was defined as severe disease.

RESULTS

We enrolled 50 cases of RSVB (median age of 2 (1-6.5) months; 40% female) and 50 age-matched controls. We observed higher values of LVTX in infants with RSVB than in controls (0.42 vs. 0.36; p = 0.008). Up to nine (18%) children presented with LVMD (LVTX > 0.5), with a higher incidence of PICU admission (89% vs. 5%; p < 0.001). The diagnostic performance of NT-proBNP in predicting LVMD was high (area under the receiver operator characteristic curve (AUC) 0.95, CI 95% 0.90-1). The diagnostic yield of the predictive model for PICU admission that included NT-proBNP was excellent (AUC 0.945, CI 95% 0.880-1), and significantly higher than the model without NT-proBNP (p = 0.026).

CONCLUSIONS

LVMD could be present in healthy infants with RSVB who develop severe disease. NT-proBNP seems to improve traditional clinical markers for outcomes.