Perinatal changes of cardiac troponin-I in normal and intrauterine growth-restricted pregnancies

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..

Differences in biomarkers of cardiac dysfunction in cord blood between normal pregnancies and pregnancies complicated by maternal diabetes

AIMS

The aim of this study was to compare biomarkers of cardiac dysfunction in cord blood in women with uncomplicated pregnancies and pregnancies complicated by maternal pre-gestational and gestational diabetes and to correlate these findings with fetal echocardiography parameters of cardiac function.

MATERIAL AND METHODS

Fetal echocardiographic assessment was performed longitudinally on 78 fetuses in the normal cohort and 32 in the diabetic cohort by measuring tricuspid annular plane systolic excursion, mitral annular plane systolic excursion, myocardial performance index, interventricular septum (IVS) thickness and left fractional shortening between July 2015 and December 2017. Cord blood samples were obtained at birth and levels of troponin I (TnI), B-type natriuretic peptide (BNP) and the amnio terminal segment of its prohormone measured.

RESULTS

Women with diabetes had significantly higher median body mass index and mean z-scores for BNP. Significant associations were observed between maternal diabetes and obesity and cord-blood BNP z-scores. The effect of diabetes on TnI levels were similar, with mean values higher in women with gestational diabetes compared to normal pregnancies; however, this difference did not reach statistical significance. These biomarker findings correlated with an increased IVS thickness in the diabetic group. No difference was demonstrated in the other cardiac function parameters measured.

CONCLUSION

Biochemical markers of cardiac dysfunction are elevated in infants of diabetic and obese mothers and correlated with increased IVS thickness.

Cardiac injury biomarkers in paediatric age: Are we there yet?

The aim of this article is to evaluate the clinical utility of cardiac injury biomarkers in paediatric age. In December 2015, a literature search was performed (PubMed access to MEDLINE citations; http://www.ncbi.nlm.nih.gov/PubMed/ ). The search strategy included the following medical subject headings and text terms for the key words: "cardiac injury biomarkers", "creatine kinase-MB", "myoglobin", "troponin", "children", "neonate/s", "newborn/s", "infant/s" and echocardiography. In the paediatric population, troponins show a good correlation with the extent of myocardial damage following cardiac surgery and cardiotoxic medication and can be used as predictors of subsequent cardiac recovery and mortality. Elevation of cardiac injury biomarkers may also have diagnostic value in cases when cardiac contusion or pericarditis is suspected. Cardiac injury biomarkers are very sensitive markers for the detection of myocardial injury and have been studied in healthy newborns, after tocolysis, intrauterine growth restriction, respiratory distress and asphyxia. The proportion of newborns with elevated troponin was higher than that in ill infants, children, and adolescents and in healthy adults, suggesting that myocardial injury, although clinically occult, is common in this young age group. Results suggest that significant elevation of cord troponin is an excellent early predictor of severity of hypoxic-ischaemic encephalopathy and mortality in term infants. Cardiac biomarkers may also benefit centres without on-site echocardiography with evidence showing good correlation with echo-derived markers of myocardial function. Further studies are needed to better clarify the role of cardiac biomarkers in paediatric age and their correlation with echocardiographic parameters.

Intermediate Diastolic Velocity as a Parameter of Cardiac Dysfunction in Growth-Restricted Fetuses

OBJECTIVE

To evaluate the intermediate intracardiac diastolic velocities in fetuses with growth restriction.

METHODS

Doppler waveforms of the two atrioventricular valves were obtained. Peak velocities of the E (early) and A (atrial) components, and the lowest intermediate velocity (IDV) between them, were measured in 400 normally grown and in 100 growth-restricted fetuses. The prevalence of abnormal IDV, E/IDV, and A/IDV ratios in fetuses presenting with perinatal death or acidemia at birth (pH ≤7.1) was estimated.

RESULTS

IDV was significantly lower and E/IDV ratios significantly higher in the two ventricles of growth-restricted fetuses with reduced diastolic velocities in the umbilical artery (p < 0.05). In 13 fetuses presenting with perinatal death or acidemia at birth, 11 (85%) had either an E/IDV or A/IDV ratio >95th percentile, whereas 5 (38%) showed absent or reversed atrial velocities in the ductus venosus (DV-ARAV; p < 0.04). Fetuses without DV-ARAV but with elevated E/IDV ratios in either ventricle were nearly 7-fold more likely to have perinatal demise or acidemia at birth (OR 6.9, 95% CI 1.4-34) than those with E/IDV ratios <95th percentile.

CONCLUSION

The E/IDV and A/IDV ratios in the two cardiac ventricles might provide information about the risk of perinatal demise or acidemia in growth-restricted fetuses.

Is meconium stained amniotic fluid related to occult myocardial injury in term low risk pregnancies?

AIM

The present study aimed to compare Troponin T (Tp T) levels of infants born with meconium stained amniotic fluid (MSAF) to those with clear amniotic fluid.

STUDY DESIGN

Case-control study

SUBJECTS

Thirty-five women who had delivery complicated by MSAF between 37 and 41weeks of gestation were defined as the study group and women with healthy uncomplicated pregnancies with clear amniotic fluid who were matched for age, parity, and gestational age were defined as the control group.

OUTCOME MEASURES

Cord blood Tp T level, gas analysis and neonatal outcomes were compared between groups.

RESULTS

Tp T levels of the study and control groups were 0.026±0.013ng/ml and 0.031±0.016ng/ml, respectively. The difference was not statistically significant (p=0.132). On the other hand, the study group had a statistically lower HCO(3) level (21.80 vs 23.60mmol/l ) and higher rate of base deficit (4.85 vs 3.25mmol/l) than the control group.

CONCLUSION

The presence of meconium during labor is not related to occult myocardial injury in low-risk term pregnancies.

Use of cardiac biomarkers in neonatology

Cardiac biomarkers are used to identify cardiac disease in term and preterm infants. This review discusses the roles of natriuretic peptides and cardiac troponins. Natriuretic peptide levels are elevated during atrial strain (atrial natriuretic peptide (ANP)) or ventricular strain (B-type natriuretic peptide (BNP)). These markers correspond well with cardiac function and can be used to identify cardiac disease. Cardiac troponins are used to assess cardiomyocyte compromise. Affected cardiomyocytes release troponin into the bloodstream, resulting in elevated levels of cardiac troponin. Cardiac biomarkers are being increasingly incorporated into clinical trials as indicators of myocardial strain. Furthermore, cardiac biomarkers can possibly be used to guide therapy and improve outcome. Natriuretic peptides and cardiac troponins are potential tools in the diagnosis and treatment of neonatal disease that is complicated by circulatory compromise. However, clear reference ranges need to be set and validation needs to be carried out in a population of interest.

Cardiac dysfunction and cell damage across clinical stages of severity in growth-restricted fetuses

OBJECTIVE

The purpose of this study was to assess cardiac function and cell damage in intrauterine growth-restricted (IUGR) fetuses across clinical Doppler stages of deterioration.

STUDY DESIGN

One hundred twenty appropriate-for-gestational-age and 81 IUGR fetuses were classified in stages 1/2/3 according umbilical artery present/absent/reversed end-diastolic blood flow, respectively. Cardiac function was assessed by modified-myocardial performance index, early-to-late diastolic filling ratios, cardiac output, and cord blood B-type natriuretic peptide; myocardial cell damage was assessed by heart fatty acid-binding protein, troponin-I, and high-sensitivity C-reactive protein.

RESULTS

Modified-myocardial performance index, blood B-type natriuretic peptide, and early-to-late diastolic filling ratios were increased in a stage-dependent manner in IUGR fetuses, compared with appropriate-for-gestational-age fetuses. Heart fatty acid-binding protein levels were higher in IUGR fetuses at stage 3, compared with control fetuses. Cardiac output, troponin-I, and high-sensitivity C-reactive protein did not increase in IUGR fetuses at any stage.

CONCLUSION

IUGR fetuses showed signs of cardiac dysfunction from early stages. Cardiac dysfunction deteriorates further with the progression of fetal compromise, together with the appearance of biochemical signs of cell damage.

Cord blood ischemia-modified albumin levels in normal and intrauterine growth restricted pregnancies

Ischemia-modified albumin (IMA) is a sensitive biomarker of cardiac ischemia. Intrauterine growth restriction (IUGR) may imply fetal hypoxia, resulting in blood flow centralization in favour of vital organs (brain, heart, adrenals—“brain sparing effect”). Based on the latter, we hypothesized that cord blood IMA levels should not differ between IUGR and appropriate-for-gestational-age (AGA) full-term pregnancies. IMA was measured in blood samples from doubly-clamped umbilical cords of 110 AGA and 57 asymmetric IUGR pregnancies. No significant differences in IMA levels were documented between AGA and IUGR groups. IMA levels were elevated in cases of elective cesarean section (P = .035), and offspring of multigravidas (P = .021). In conclusion, “brain sparing effect” is possibly responsible for the lack of differences in cord blood IMA levels at term, between IUGR and AGA groups. Furthermore, higher oxidative stress could account for the elevated IMA levels in cases of elective cesarean section, and offspring of multigravidas.