Do B-type natriuretic peptide levels accurately predict outcome in infants with congenital diaphragmatic hernia?

Abstract

We have read with interest the study by Guslits et al that investigated the prognostic effect of B-type natriuretic peptide (BNP) in predicting the outcomes of infants with congenital diaphragmatic hernia (CDH).1Guslits E. Steurer M.A. Nawaytou H. Keller R.L. Longitudinal B-type natriuretic peptide levels predict outcome in infants with congenital diaphragmatic hernia.J Pediatr. 2021.; 229: 191-198Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar Infants with atrial septal defect, ventricular septal defect, or patent ductus arteriosus were included. However, it may be important to exclude subjects with any other disease that influences ventricular volume expansion and pressure overload, because BNP is a cardiac neurohormone secreted by the ventricles in response to volume expansion and pressure overload.2Maisel A.S. Krishnaswamy P. Nowak R.M. McCord J. Hollander J.E. Duc P. et al.Rapid measurement of B-type natriuretic peptide in the emergency diagnosis of heart failure.N Engl J Med. 2002; 347: 161-167Crossref PubMed Scopus (2759) Google Scholar We are very interested in the echocardiographic parameters of those infants, to understand if these heart diseases could have an impact on their right volume and pressure. Alternatively, an additional control group with similar heart diseases but without CDH could be included. In the present study, the authors sought additional biomarkers that could longitudinally assess illness severity due to pulmonary vascular disease and right ventricle dysfunction.1Guslits E. Steurer M.A. Nawaytou H. Keller R.L. Longitudinal B-type natriuretic peptide levels predict outcome in infants with congenital diaphragmatic hernia.J Pediatr. 2021.; 229: 191-198Abstract Full Text Full Text PDF PubMed Scopus (4) Google Scholar The measurements of pulmonary hypertension and right ventricle performance provided by echocardiography are variable and less consistent with the clinical outcomes of CDH.3Patel N. Lally P.A. Kipfmueller F. Massolo A.C. Luco M. Van Meurs K.P. et al.Ventricular dysfunction is a critical determinant of mortality in congenital diaphragmatic hernia.Am J Respir Crit Care Med. 2019; 200: 1522-1530Crossref PubMed Scopus (40) Google Scholar,4Patel N. Massolo A.C. Paria A. Stenhouse E.J. Hunter L. Finlay E. et al.Early postnatal ventricular dysfunction is associated with disease severity in patients with congenital diaphragmatic hernia.J Pediatr. 2018; 203 (400-7.e1)Abstract Full Text Full Text PDF PubMed Scopus (36) Google Scholar It is of interest to see the advantage of BNP over echocardiography in the same cohort. In addition, the authors performed receiver operating characteristic curves to identify BNP cut-offs for maximizing correct outcome classification at each time point. They concluded that BNP accurately predicted outcome at 3-5 weeks. However, the total sample size of 49 infants may be not enough to acquire an accurate information on BNP cut-off, consistent with the wide ranges of the 95% CIs. When the hypothesized area under the receiver operating characteristic curve is approximate to 0.8, as provided by this study, the estimated sample size should be no less than 208-274 (area under the receiver operating characteristic curve = 0.8 ± 0.1) subjects (Figure; available at www.jpeds.com).5Power Analysis & Sample Size, PASS.https://www.ncss.com/software/pass/Google Scholar,6Negida A. Fahim N.K. Negida Y. Sample size calculation guide—part 4: how to calculate the sample size for a diagnostic test accuracy study based on sensitivity, specificity, and the area under the ROC curve.Adv J Emerg Med. 2019; 3: e33PubMed Google Scholar ReplyThe Journal of PediatricsVol. 229PreviewWe thank Drs Tang and Ji for their interest, correspondence, and thoughtful queries regarding our manuscript. To address their first question about the inclusion of infants with patent ductus arteriosus (PDA), atrial septal defect (ASD), and ventricular septal defect (VSD), we chose to include these cardiovascular defects to increase the generalizability of our data to the typical congenital diaphragmatic hernia (CDH) population, as these conditions are either part of the physiology of CDH or are more likely to be diagnosed in the relevant time period due to serial echocardiography. Full-Text PDF Longitudinal B-Type Natriuretic Peptide Levels Predict Outcome in Infants with Congenital Diaphragmatic HerniaThe Journal of PediatricsVol. 229PreviewTo evaluate B-type natriuretic peptide (BNP) as a longitudinal biomarker of clinical outcome in infants with congenital diaphragmatic hernia (CDH). Full-Text PDF