Troponin

Cardiac Troponin-I Level at 24 hours of Age in Stable Newborn Infants Born at ≥35 Weeks of Gestation

OBJECTIVE

 Cardiac troponin-I is a known biomarker of myocardial injury in adults and children but its diagnostic utility is unclear in newborns.This study aimed to establish normative data for troponin-I in stable newborns and assess any variation due to maternal diabetes status, mode of delivery, and Apgar scores.

STUDY DESIGN

 Prospective, observational study of stable newborn ≥35 weeks gestation admitted to a well-baby nursery at a single institution. Infants with respiratory distress, congenital infections, malformations, or syndromes were excluded. Troponin-I values were obtained by a validated point-of-care capillary blood sample at 24 hours of age.

RESULTS

 A total of 132 patients were included for analysis. Thirteen infants were born to mothers with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during pregnancy and analyzed as a subgroup, with the remaining 119 infants comprising the base cohort to establish baseline normative troponin-I levels in stable newborn infants. The mean (standard deviation) troponin-I level of infants in the base cohort group was 0.019 ± 0.018 ng/mL and in infants born with maternal SARS-CoV-2 infection during pregnancy troponin-I level was 0.081 ± 0.1 ng/mL (p < 0.001). In infants of the base cohort, there was no significant difference in troponin-I levels between diabetic versus nondiabetic mothers, vaginal birth versus cesarean section, and 5-minute Apgar score of <7 versus ≥7.

CONCLUSION

 Cardiac troponin-I level in healthy term newborns was 0.019 ± 0.018 ng/mL, which conforms to healthy children and adult lab values. There was no statistically significant difference in troponin-I levels in infants of maternal diabetes or normal glucose status, mode of delivery, cesarean versus vaginal, or 5-minute Apgar score of <7 or ≥7. Troponin-I levels in asymptomatic neonates born to mothers with a history of SARS-CoV-2 during pregnancy demonstrated an elevation when compared to the baseline group of infants.

KEY POINTS

· Troponin-I level, biomarker of myocardial injury, in newborns not requiring delivery-room.. · Resuscitation is comparable to normal pediatric & adult population independent of mode of delivery or maternal diabetes status..

How to interpret cardiac biomarkers in children?

Cardiac biomarkers are used as first-line diagnostic tools in suspected myocardial injury and heart failure in adult patients. Their use in paediatric patients has been limited by variability caused by age, gender and the presence of an underlying congenital cardiac condition. There are established reference ranges for both NT-proBNP and troponin in healthy children, but these cannot be applied to all paediatric patients because of limited large studies focusing on children with congenital heart disease and/or cardiomyopathy.This article will focus on the pathophysiology of myocardial injury and heart failure in children and the subsequent cardiac biomarker correlation. It will explain how to interpret the biomarker assay levels obtained for both troponin and NT-proBNP and highlights the importance of a clear clinical question prior to requesting a cardiac biomarker assay level.Clinical cases outline scenarios that may prompt consideration of biomarker analysis in children and aims to equip the reader with an understanding of how to interpret the results.