Old tool - new application: NT-proBNP in fetal medicine

Cardiac function impairment in recipient twins of twin-to-twin transfusion syndrome: Insights from NT-proBNP levels in amniotic fluid

OBJECTIVES

To investigate changes in N-terminal pro-brain natriuretic peptide (NT-proBNP) levels in the amniotic fluid of recipient twins with twin-twin transfusion syndrome (TTTS), analyze the correlation between NT-proBNP and cardiac linear measurements, and assess the feasibility of NT-proBNP as a biochemical marker for fetal cardiac function.

DESIGN AND METHODS

A total of 47 pregnancies with TTTS, 21 idiopathic polyhydramnios pregnancies, and 114 normal singleton pregnancies were included from Xiangya Hospital of Central South University between October 2020 and July 2023. Fetal cardiac linear parameters, amniotic fluid depth, and NT-proBNP levels in amniotic fluid were measured across the three groups. The correlation of NT-proBNP with amniotic fluid depth, cardiac linear parameters, and CHOP score in TTTS recipients was analyzed.

RESULTS

There was no statistically significant difference in amniotic fluid NT-proBNP levels and cardiac linear parameters between idiopathic polyhydramnios and normal singletons. However, NT-proBNP levels and cardiac parameters in TTTS recipient twins were significantly higher than in the other two groups (p < 0.05). After adjusting for gestational variables, NT-proBNP levels in TTTS recipients showed significant correlations with atrial and ventricular diameters, ventricular wall thickness, cardiothoracic ratio, and CHOP score.

CONCLUSIONS

Amniotic fluid NT-proBNP is a sensitive and objective biochemical marker for assessing fetal cardiac function, independent of amniotic fluid volume. It serves as a valuable complement to echocardiographic assessment in evaluating the severity of fetal heart failure in TTTS recipients.

Fetal NT-proBNP levels and their course in severe anemia during intrauterine treatment

PURPOSE

In adults and fetuses, N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a marker of cardiac failure and myocardial remodelling. We examined the effect of anemia and intrauterine transfusion (IUT) on NT-proBNP concentrations in fetuses with anemia and established gestational age-dependent reference values of a control group.

METHODS

We analyzed NT-proBNP levels in anemic fetuses that underwent serial intrauterine transfusions (IUT), focusing on different causes and severity of anemia and comparing the results to a non-anemic control group.

RESULTS

In the control group, the average NT-proBNP concentration was 1339 ± 639 pg/ml, decreasing significantly with increasing gestational age (R = - 74.04, T = - 3.65, p = 0.001). Subjects had significantly higher NT-proBNP concentrations before initiation of IUT therapy (p < 0.001), showing fetuses with parvovirus B19 (PVB19) infection having the highest concentrations. Hydropic fetuses also showed an increased NT-proBNP concentration compared to non-hydropic fetuses (p < 0.001). During the course of therapy, NT-proBNP concentration before subsequent IUT decreased significantly from pathologically high levels, while MoM-Hb and MoM-MCA-PSV remained pathological.

CONCLUSION

NT-pro BNP levels in non-anemic fetuses are higher than in postnatal life, decreasing with ongoing pregnancy. Anemia is a hyperdynamic state and its severity correlates with circulating NT-proBNP levels. Highest concentrations occur in fetuses with hydrops and with PVB19 infection, respectively. Treatment by IUT leads to a normalisation of NT-proBNP concentrations, so the measurement of its levels may be useful in therapy monitoring.

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.

Factors affecting N-terminal pro-B-type natriuretic peptide levels in preterm infants and use in determination of haemodynamic significance of patent ductus arteriosus

This study aimed to investigate factors affecting N-terminal pro-B-type natriuretic peptide (NTproBNP) in preterm infants and the ability of NTproBNP to predict haemodynamically significant patent ductus arteriosus (HsPDA). Prospective cohort study of 51 infants < 30 weeks gestation. Blood NTproBNP and heart ultrasound were performed on day of life 3, 10, 28 and 36 weeks corrected age. NTproBNP levels analysed for prediction of HsPDA. The effect of gestational age, ventilation, hypoxia, bronchopulmonary dysplasia (BPD), creatinine and haemoglobin levels on NTproBNP levels were investigated. Infants with HsPDA had higher mean (SD) day 3 NTproBNP (1840 pmol/L (1058) versus 178 pmol/L (140) p < 0.001). Receiver operator curves of day 3 NTproBNP for prediction of day 3 and day 10 HsPDA had an area under the curve of 0.98 and 0.94, respectively. A chosen day 3 NTproBNP value of ≥ 287 pmol/L for the prediction of day 3 HsPDA correctly classified 92% (sensitivity 92%, specificity 92%). NTproBNP demonstrated only modest ability to predict severe BPD. Chronological but not gestational age affected NTproBNP. Ventilation, hypoxia and haemoglobin levels did not influence NTproBNP but creatinine level was positively correlated.

CONCLUSION

Day 3 NTproBNP is a useful biomarker to predict HsPDA and may be a valuable tool in future trial design. What is Known: • NTproBNP is a cardiac hormone used to diagnose and monitor cardiac dysfunction in adults and has been shown to be higher in premature infants with haemodynamically significant ductus arteriosus (HsPDA). What is new: • NTproBNP is highly predictive of ultrasound-defined HsPDA and may be a useful tool for further triage • Early NTproBNP higher in infants who develop severe BPD and with renal impairment but not affected by gestational age, recent exposure to hypoxia or haemoglobin levels while late levels unexpectedly higher in those without BPD or HsPDA.

What Is High Enough? Elevated NT-pro-BNP in Decompensated Paroxysmal Supraventricular Tachycardia

Since the late 1980s, elevated atrial natriuretic peptide (ANP) was considered the cause of brisk diuresis in adult patients with paroxysmal supraventricular tachycardia (PSVT). Pro-brain natriuretic peptide (pro-BNP) and related molecules, e.g., N-terminal pro b-type natriuretic peptide (NT-pro-BNP) are known biomarkers of heart failure in adult patients from many causes with probable relevance in children. Perhaps, pro-BNP or related molecules such as NT-pro-BNP are useful in the management of PSVT in infants, thus hastening treatment in children who may otherwise significantly decompensate. Case series of one infant and two neonates presenting with cardiogenic shock and evidence of heart failure are presented. Cardiac monitoring or electrocardiogram (ECG) confirmed the presence of PSVT. Adenosine was administered resulting in successful chemical cardioversion with each case. Significantly elevated NT-pro-BNP levels correlated with heart failure prior to cardioversion. In each case, patients were discharged home with lower NT-pro-BNP levels and maintenance with a β-blocker. Due to documented relationships between elevated pro-BNP level and heart failure in adults, the authors measured the related biomarker NT-pro-BNP in each case, as the relationship could be similar in pediatric PSVT. Based on our experience with children in acute heart failure from other causes, NT-pro-BNP can increase to potentially extreme levels in infants. It appears to correlate with clinical signs of insufficient cardiac output, such as tachycardia, respiratory distress, and moribund appearance. Indeed, in the case series, extremely high NT-pro-BNP values were obtained when the patients appeared moribund from decompensated PSVT. The question arising from these observations is: At what level of elevated NT-pro-BNP, would patients be identified for cardioversion prior to appearance of other signs and symptoms? For each patient within the case series, NT-pro-BNP levels of approximately 20,000 pg/mL were indicative of decompensated heart failure, which was subsequently confirmed by examination of the patient. Further investigation is needed to determine the clinical significance of NT-pro-BNP and related peptides in pediatric patients with PSVT and intermittent PSVT. However, the possibility exists that an increase in NT-pro-BNP and related peptides could be a biomarker for cardiac decompensation after prolonged or intermittent PSVT, thereby shortening the time of diagnosis and intervention, and hence, potentially preventing morbidity, mortality, and extended hospitalization. Additional evidence-based research would help provide biomarker information during PSVT allowing practitioners to more objectively analyze risks.

Cardiac Manifestations of Twin–to–Twin Transfusion Syndrome

This review addresses the physiology of monochorionic diamniotic (MC/DA) twins and the potential for twin–twin transfusion syndrome (TTTS). It focuses on the underlying cardiovascular pathophysiology of TTTS and the cardiovascular impact of TTTS for both the recipient and the donor twin. It explains the principles for assessment and monitoring of these cardiovascular changes and how these may be used to guide pregnancy management. Finally, it describes the effect of treatment on the altered hemodynamics and how this can influence pregnancy and perinatal management, as well as longer-term follow-up.

Distribution of soluble suppression of tumorigenicity 2 (sST2), N-terminal pro-brain natriuretic peptide (NT-proBNP), high sensitive troponin I and high-sensitive troponin T in umbilical cord blood

Background:

Soluble suppression of tumorigenicity 2 (sST2), N-terminal pro-brain natriuretic peptide (NT-proBNP), high sensitive troponin I (hs-TnI), and high sensitive troponin T (hs-TnT) are representative cardiac biomarkers. The reference intervals (RIs) of these biomarkers have been rarely investigated in umbilical cord blood (UCB). We explored the distribution of these cardiac markers and established their RIs in UCB.

Methods:

In a total of 293 UCB specimens, sST2, NT-proBNP, hs-TnI, and hs-TnT concentrations were analyzed according to the gestational age, presence of premature membrane rupture (PROM), presence of gestational diabetes mellitus (GDM), and Apgar score at 1 min. Their RIs were defined in 133 UCB specimens from healthy, full-term neonates, using non-parametric percentile methods according to the Clinical and Laboratory Standards Institute guideline (EP28-A3C).

Results:

The concentrations of four cardiac markers in UCB were different between full-term neonates and pre-term neonates. The concentrations of NT-proBNP and hs-TnI differed according to the presence or absence of PROM. Their concentrations did not differ regardless of the presence of GDM. The concentrations of sST2 and NT-proBNP differed according to the Apgar score at 1 min. The 97.5th percentile upper reference limits were: sST2, 59.9 ng/mL; NT pro-BNP, 1415.3 pg/mL; hs-TnI, 27.8 pg/mL; and hs-TnT, 86.5 pg/mL.

Conclusions:

The distribution of sST2, NT pro-BNP, hs-TnI, and hs-TnT in UCB together with their RIs would provide fundamental data for future researches and clinical practice.

Serum Biomarkers of Inflammation, Fibrosis, and Cardiac Function in Facilitating Diagnosis, Prognosis, and Treatment of Anti-SSA/Ro-Associated Cardiac Neonatal Lupus

BACKGROUND

Cardiac manifestations of neonatal lupus (cardiac NL) include congenital heart block and cardiomyopathy. Several candidate biomarkers were evaluated in cases at risk for cardiac NL on the basis of potential roles in inflammation, fibrosis, and cardiac dysfunction: C-reactive protein (CRP); NT-pro-B-type natriuretic peptide (NT-proBNP); troponin I; matrix metalloproteinase (MMP)-2; urokinase plasminogen activator (uPA); urokinase plasminogen activator receptor (uPAR); plasminogen; and vitamin D.

OBJECTIVES

Identification of maternal and fetal biomarkers associated with development and morbidity of cardiac NL should provide clues to pathogenesis with translational implications for management.

METHODS

Cord (139) and maternal (135) blood samples collected during pregnancies at risk for cardiac NL were available for study. Levels of cord and maternal CRP, cord NT-proBNP, and cord troponin I were evaluated using multiplex assays. Cord and maternal vitamin D were assessed by liquid chromatography-mass spectrometry. MMP-2, uPA, uPAR, and plasminogen were evaluated using ELISA.

RESULTS

Cord CRP, NT-proBNP, MMP-2, uPA, uPAR, and plasminogen levels were higher in cardiac NL-affected fetuses than in unaffected cases, independent of maternal rheumatic disease, season at highest risk of cardiac NL development, and medications taken during pregnancy. These biomarkers were positively associated with a disease severity score derived from known risk factors for mortality in cardiac NL. Maternal CRP and cord troponin I levels did not differ between the groups. Cord and maternal vitamin D levels were not significantly associated with cardiac NL, but average maternal vitamin D level during pregnancy was positively associated with longer time to postnatal pacemaker placement.

CONCLUSIONS

These data support the association of fetal reactive inflammatory and fibrotic components with development and morbidity of cardiac NL. Following CRP and NT-proBNP levels after birth can potentially monitor severity and progression of cardiac NL. MMP-2 and the uPA/uPAR/plasminogen cascade provide therapeutic targets to decrease fibrosis. Although decreased vitamin D did not confer increased risk, given the positive influence on postnatal outcomes, maternal levels should be optimized.

Reference intervals for N-terminal pro-B-type natriuretic peptide in amniotic fluid between 10 and 34 weeks of gestation

BACKGROUND

In adult and pediatric cardiology, n-terminal pro-B-type natriuretic peptide (nt-proBNP) serves as biomarker in the diagnosis and management of cardiovascular dysfunction. Elevated levels of circulating nt-proBNP are present in fetal conditions associated with myocardial pressure or volume load. Compared to fetal blood sampling, amniocentesis is technically easier and can be performed from early pregnancy onwards. We aimed to investigate amniotic fluid (AF) nt-proBNP concentrations in normal pregnancies between 10 and 34 weeks of gestation.

METHODS

Nt-proBNP and total protein (TP) was measured in AF by chemiluminescence assay (photometry, respectively). To adjust for a potential dilutional effect, the AF-nt-proBNP/AF-TP ratio was analyzed. Reference intervals were constructed by regression modeling across gestational age.

RESULTS

132 samples were analyzed. A negative correlation between AF-nt-proBNP/AF-TP ratio and gestational age was observed. Curves for the mean and the 5% and 95% reference interval between 10 and 34 weeks of gestation were established.

CONCLUSION

In normal pregnancy, nt-proBNP is present in AF and decreases during gestation. Our data provide the basis for research on AF-nt-proBNP as biomarker in fetal medicine.