Relationship between maternal hemodynamics and plasma natriuretic peptide concentrations during pregnancy complicated by preeclampsia and fetal growth restriction

N-terminal prohormone of brain natriuretic peptide in gestational hypertension and preeclampsia - State of the art

N-terminal prohormone of brain natriuretic peptide (NT-proBNP) is a non-active prohormone secreted by ventricular cardiomyocytes into the circulation in response to ventricle overload, mainly due to increased blood volume. The changes in NT-proBNP levels during pregnancy have been investigated in multiple studies. In the case of hypertensive disorders of pregnancy, increased vasoconstriction leads to increased blood pressure and afterload. Together with the volume overload of pregnancy, it leads to higher NT-proBNP secretion. As hypertensive disorders of pregnancy are among the leading causes of prematurity and perinatal mortality, early prediction and diagnosis of gestational hypertension, and preeclampsia are essential for improving maternal and infant prognosis. NT-proBNP has been regarded as a potential biomarker of hypertensive disorders of pregnancy. In this review, we have thoroughly summarized the current data on the prognostic and diagnostic utility of NT-proBNP in patients with gestational hypertension and preeclampsia. NT-proBNP values may help distinguish between non-preeclamptic and preeclamptic patients, even if there are no significant differences in blood pressure. Moreover, in pregnancies complicated by preeclampsia, the value of increased NT-proBNP level is related to the stage and the severity of the disease. Further improvement of our knowledge about NT-proBNP as a diagnostic biomarker and a putative predictor of adverse cardiac events in women with hypertensive disorders of pregnancy should lead to better management of these patients.

Genetic Associations of Circulating Cardiovascular Proteins With Gestational Hypertension and Preeclampsia

Importance

Hypertensive disorders of pregnancy (HDPs), including gestational hypertension and preeclampsia, are important contributors to maternal morbidity and mortality worldwide. In addition, women with HDPs face an elevated long-term risk of cardiovascular disease.

Objective

To identify proteins in the circulation associated with HDPs.

Design, Setting, and Participants

Two-sample mendelian randomization (MR) tested the associations of genetic instruments for cardiovascular disease-related proteins with gestational hypertension and preeclampsia. In downstream analyses, a systematic review of observational data was conducted to evaluate the identified proteins' dynamics across gestation in hypertensive vs normotensive pregnancies, and phenome-wide MR analyses were performed to identify potential non-HDP-related effects associated with the prioritized proteins. Genetic association data for cardiovascular disease-related proteins were obtained from the Systematic and Combined Analysis of Olink Proteins (SCALLOP) consortium. Genetic association data for the HDPs were obtained from recent European-ancestry genome-wide association study meta-analyses for gestational hypertension and preeclampsia. Study data were analyzed October 2022 to October 2023.

Exposures

Genetic instruments for 90 candidate proteins implicated in cardiovascular diseases, constructed using cis-protein quantitative trait loci (cis-pQTLs).

Main Outcomes and Measures

Gestational hypertension and preeclampsia.

Results

Genetic association data for cardiovascular disease-related proteins were obtained from 21 758 participants from the SCALLOP consortium. Genetic association data for the HDPs were obtained from 393 238 female individuals (8636 cases and 384 602 controls) for gestational hypertension and 606 903 female individuals (16 032 cases and 590 871 controls) for preeclampsia. Seventy-five of 90 proteins (83.3%) had at least 1 valid cis-pQTL. Of those, 10 proteins (13.3%) were significantly associated with HDPs. Four were robust to sensitivity analyses for gestational hypertension (cluster of differentiation 40, eosinophil cationic protein [ECP], galectin 3, N-terminal pro-brain natriuretic peptide [NT-proBNP]), and 2 were robust for preeclampsia (cystatin B, heat shock protein 27 [HSP27]). Consistent with the MR findings, observational data revealed that lower NT-proBNP (0.76- to 0.88-fold difference vs no HDPs) and higher HSP27 (2.40-fold difference vs no HDPs) levels during the first trimester of pregnancy were associated with increased risk of HDPs, as were higher levels of ECP (1.60-fold difference vs no HDPs). Phenome-wide MR analyses identified 37 unique non-HDP-related protein-disease associations, suggesting potential on-target effects associated with interventions lowering HDP risk through the identified proteins.

Conclusions and Relevance

Study findings suggest genetic associations of 4 cardiovascular disease-related proteins with gestational hypertension and 2 associated with preeclampsia. Future studies are required to test the efficacy of targeting the corresponding pathways to reduce HDP risk.

Intrapartum trends of NT-proBNP and hs-cTnT in patients with severe features of preeclampsia

BACKGROUND

Preeclampsia with severe features (SPE) is a multisystem syndrome associated with long-term cardiovascular morbidity. Serum concentrations of N-terminal B-type natriuretic peptide (NT-proBNP) and high sensitivity cardiac troponin-T (hs-cTnT) are sensitive markers of cardiac stretch and ischemia, respectively.

OBJECTIVE

Our aim was to examine NT-proBNP and hs-cTnT in patients with SPE during labor. We hypothesized that patients with severe preeclampsia would have increased serum concentrations of these analytes as compared with normotensive laboring patients.

STUDY DESIGN

This was a prospective cohort study of intrapartum patients with SPE and normotensive controls. Patients were recruited at the time of SPE diagnosis or admission to the labor unit, and those with medical conditions that could predispose to baseline cardiac dysfunction were excluded. Serum from venous blood was collected for NT-proBNP and hs-cTnT measurement at three time points: 0-2 h, 4 h, and 12 h after admission. A mixed random effects regression model was used to compare analyte levels at each time point and to compare trends over time. The primary outcome was NT-proBNP concentration at each collection time point in patients with severe preeclampsia as compared to normotensive controls. Power analysis yielded a goal sample of 25 patients with a 12 h and at least 1 other sample in each arm. Two-tailed P values less than 0.05 were considered statistically significant. P value adjustment for multiple comparisons was performed.

RESULTS

Of 78 patients analyzed, 36 had severe preeclampsia and 42 were normotensive controls with 25 in each cohort having a 12 h and at least 1 other sample. The NT-proBNP trend was significantly different in the two cohorts (P < 0.001). After adjustment for multiple comparisons, the mean serum concentration of NT-proBNP was elevated in the severe preeclampsia group at 0-2 and 4 h, but not at 12 h. After similar adjustment, detectable serum concentrations of hs-cTnT were more frequent in patients with severe preeclampsia at all three timepoints.

CONCLUSION

Intrapartum serum concentrations of NT-proBNP were elevated nearly twofold in patients with SPE when compared with normotensive controls, with the most pronounced differences found during early labor. Detectable but low serum concentrations of hs-cTnT were more common in women with severe preeclampsia as compared with normotensive controls. These findings suggest cardiac dysfunction with SPE may be present at the time of admission and contribute to features of maternal cardiovascular morbidity and mortality.

Lack of an association between first-trimester concentration of mid-regional pro-atrial natriuretic peptide and risk of early-onset preeclampsia <34 weeks' gestation

AIM

We examined the heart failure biomarker mid-regional pro-atrial natriuretic peptide during the first trimester of pregnancy in relation to early-onset preeclampsia <34 weeks.

MATERIALS AND METHODS

This case-control study included 34 women with singleton pregnancies with a preeclampsia diagnosis and delivery before 34 weeks of gestation who had attended the routine first-trimester ultrasound scan at 11-13+6 weeks of gestation between August 2010 and October 2015 at the Copenhagen University Hospital Rigshospitalet, Denmark, and 91 uncomplicated singleton pregnancies matched by time of the routine first-trimester blood sampling at 8-13+6 weeks. Descriptive statistical analyses were performed for maternal characteristics and obstetric and medical history for the case versus the control group. Concentrations of mid-regional pro-atrial natriuretic peptide, placental growth factor, soluble fms-like tyrosine kinase-1, and pregnancy-associated plasma protein A between early-onset preeclampsia cases and the control group were compared using Students t-test and the Mann-Whitney U test. Biochemical marker concentrations were converted into multiples of the expected median values after adjustment for gestational age.

RESULTS

Mid-regional pro-atrial natriuretic peptide levels were not significantly different between early-onset preeclampsia cases and the control group in the first trimester of pregnancy. As expected, both placental growth factor and pregnancy-associated plasma protein A levels were significantly lower in early-onset preeclampsia, whereas soluble fms-like tyrosine kinase-1 levels were not statistically significantly different.

CONCLUSION

The maternal first-trimester concentration of mid-regional pro-atrial natriuretic peptide, a peptide with multiple biological functions including a relation to cardiovascular disease, was not significantly different in women with early-onset preeclampsia.

Assessing maternal cardiac function by obstetricians: technique and reference ranges

BACKGROUND

A strong body of evidence has now coalesced indicating that some obstetrical syndromes may result from maladaptive responses of the maternal cardiovascular system. Longitudinal studies have shown that these changes are complex and present before the clinical recognition of preeclampsia and fetal growth restriction, suggesting that hemodynamic maladaptation may play an etiologic role in obstetrical complications. Chronic hypertension is one of the most frequent complications of pregnancy, and recent evidence suggests that control of mild hypertension in early pregnancy improves outcome. The management of chronic hypertension can be improved by understanding specific cardiovascular hemodynamic abnormalities such as increased cardiac output or increased systemic vascular resistance, which can respond to either beta or calcium channel blockers, depending on the hemodynamic findings. Evaluation of maternal cardiac function has not been previously available to obstetrical healthcare providers using diagnostic ultrasound equipment used for fetal evaluation.

OBJECTIVE

Obstetrical ultrasound machines may be configured for various probes (endovaginal, abdominal, 3D/4D, and cardiac). This study used a cardiac probe placed in the suprasternal notch to image and measure the descending aorta diameter and the velocity time integral using pulsed and continuous wave Doppler ultrasound in normal pregnant women between 11 and 39 weeks of gestation. These measurements were followed by computation of maternal left ventricular preload, afterload, contractility, and blood flow.

STUDY DESIGN

This was a prospective cross-sectional study. A total of 400 pregnant women were recruited between 11 and 39 weeks of gestation. Imaging of the maternal aortic arch was performed by placing a cardiac probe in the suprasternal notch to identify the aortic arch using 2D and color Doppler ultrasound. The end-systolic diameter of the aorta was measured at the junction of the left subclavian artery with the descending aorta, which was followed by insonation of the descending aorta to obtain the Doppler waveform. Following insonation of the descending aorta, measurements of the aortic diameter, velocity time integral, ejection time, mean pressure gradient, heart rate, maternal weight and height, and systolic and diastolic blood pressures were entered into an Excel spreadsheet to compute the following: (1) preload measurements of stroke volume, stroke volume index, and stroke work index; (2) afterload measurements of systemic vascular resistance and the potential-to-kinetic energy ratio; (3) contractility measurements of inotropy and the Smith-Madigan inotropy index; and (4) blood flow measurements of cardiac output and the cardiac output index. Fractional polynomial regression analysis was performed for each of the above measurements using gestational age as the independent variable.

RESULTS

The diastolic and mean arterial blood pressure decreased from 11 to 18 weeks of gestation and then increased until term. The afterload measurements demonstrated similar characteristics, as all values decreased from 11 weeks until the mid and late second trimester, after which all values increased until term. Changes in contractility demonstrated an increase from 11 weeks to 25 to 28 weeks, followed by a decline until term. Changes in blood flow demonstrated an increase from 11 to 27 weeks and then declined until term. The continuous wave Doppler values were greater than the pulsed Doppler values except for the contractility measurements. Examples of abnormal cardiac measurements were identified in pregnant patients with hypertension and fetal growth restriction. An Excel calculator was created to provide quick computation of z-score measurements and their corresponding centiles described in this study.

CONCLUSION

The technique for evaluation of maternal cardiac function described in this study would allow screening of maternal left ventricular preload, afterload, contractility, and blood flow in the obstetrical clinical milieu once a cardiac probe is acquired for obstetrical ultrasound machines used for fetal evaluation. The above measurements would allow the clinician to select appropriate hypertensive medication on the basis of the results of the evaluation of the maternal left ventricle.

The use of loop diuretics in the context of hypertensive disorders of pregnancy: a systematic review and meta-analysis

AIMS

Addressing volume expansion may improve the management of hypertension across the pregnancy continuum. We conducted a systematic review to summarize the evidence on the use of loop diuretics in the context of hypertensive disorders during pregnancy and the postpartum period.

METHODS AND RESULTS

Medline, Embase, Cochrane library, ClinicalTrials.gov, and Google Scholar were searched for original research articles published up to 29 June 2021. Of the 2801 results screened, 15 studies were included: eight randomized controlled trials, six before-after studies, and one cohort study. Based on random effects meta-analysis of before-after studies, antepartum use of loop diuretics was associated with lower DBP [mean difference -17.73 mmHg, (95% confidence intervals -34.50 to -0.96); I2 = 94%] and lower cardiac output [mean difference -0.75 l/min, (-1.11 to -0.39); I2 = 0%], with no difference in SBP, mean arterial pressure, heart rate, or total peripheral resistance. Meta-analysis of randomized controlled trials revealed that postpartum use of loop diuretics was associated with decreased need for additional antihypertensive patients [relative risk 0.69, (0.50-0.97); I2 = 14%], and an increased duration of hospitalization [mean difference 8.80 h, (4.46-13.14); I2 = 83%], with no difference in the need for antihypertensive therapy at hospital discharge, or persistent postpartum hypertension.

CONCLUSION

Antepartum use of loop diuretics lowered DBP and cardiac output, while their postpartum use reduced the need for additional antihypertensive medications. There was insufficient evidence to suggest a clear benefit. Future studies focusing on women with hypertensive pregnancy disorders who may most likely benefit from loop diuretics are required.

Maternal Serum and Umbilical Cord Brain Natriuretic Peptide Levels in Fetuses with Intrauterine Growth Restriction

Aim: We compared maternal serum and fetal cord blood proBNP levels in healthy pregnancies to those with intrauterine growth restriction (IUGR). Methods: Prospectively, maternal and cord blood samples at childbirth of 40 pregnant women with isolated IUGR and 40 healthy pregnant women were evaluated for ProBNP levels. Results: The mean serum ProBNP level was significantly higher in newborn cord blood with IUGR than in the control group (181.28 ± 145.37 vs. 91.41 ± 49.77 pg/mL, p = <0.01). Mean serum ProBNP level trended higher in women with IUGR compared to the controls, but was not statistically significant (124.21 ± 113.32 vs. 88.73 ± 85.18 pg/mL, p= >0.05). Conclusion: Third trimester mean proBNP in fetal cord blood are increased in IUGR fetuses at term birth compared to pregnancies with normal fetal growth.

The Utilization and Interpretation of Cardiac Biomarkers During Pregnancy: JACC: Advances Expert Panel

Cardiac biomarkers are widely used in the nonpregnant population when acute cardiovascular (CV) pathology is suspected; however, the behavior of these biomarkers in the context of pregnancy is less well understood. Pregnant individuals often have symptoms that mimic those of cardiac dysfunction, and complications of pregnancy may include CV disease. This paper will summarize our current knowledge on the use of cardiac biomarkers in pregnancy and provide suggestions on how to use these tools in clinical practice based on the available evidence. Natriuretic peptides and troponin should not be measured routinely in uncomplicated pregnancy, where values should remain low as in the nonpregnant population. In the context of pre-existing or suspected CV disease, these biomarkers retain their negative predictive value. Elevations of both natriuretic peptides and troponin may occur without clear clinical significance in the immediate postpartum period. Elevations of these markers should always prompt further investigation into possible CV pathology.

Maternal hemodynamics and computerized cardiotocography during labor with epidural analgesia

PURPOSE

To analyze the mechanisms involved in the fetal heart rate (FHR) abnormalities after the epidural analgesia in labor.

METHODS

A prospective unblinded single-center observational study on 55 term singleton pregnant women with spontaneous labor. All women recruited underwent serial bedside measurements of the main hemodynamic parameters using a non-invasive ultrasound system (USCOM-1A). Total vascular resistances (TVR), heart rate (HR), stroke volume (SV), cardiac output (CO) and arterial blood pressure were measured before epidural administration (T0), after 5 min 5 (T1) from epidural bolus and at the end of the first stage of labor (T2). FHR was continuously recorded through computerized cardiotocography before and after the procedure.

RESULTS

The starting CO was significantly higher in a subgroup of women with low TVR than in women with high-TVR group. After the bolus of epidural analgesia in the low-TVR group there was a significant reduction in CO and then increased again at the end of the first stage, in the high-TVR group the CO increased insignificantly after the anesthesia bolus, while it increased significantly in the remaining part of the first stage of labor. On the other hand, CO was inversely correlated with the number of decelerations detected on cCTG in the 1 hour after the epidural bolus while the short-term variation was significantly lower in the group with high-TVR.

CONCLUSION

Maternal hemodynamic status at the onset of labor can make a difference in fetal response to the administration of epidural analgesia.

Cardiac dysfunction and remodeling regulated by anti-angiogenic environment in patients with preeclampsia: the ANGIOCOR prospective cohort study protocol

Background

Cardiovascular diseases (CVD) are cause of increased morbidity and mortality in spite of advances for diagnosis and treatment. Changes during pregnancy affect importantly the maternal CV system. Pregnant women that develop preeclampsia (PE) have higher risk (up to 4 times) of clinical CVD in the short- and long-term. Predominance of an anti-angiogenic environment during pregnancy is known as main cause of PE, but its relationship with CV complications is still under research. We hypothesize that angiogenic factors are associated to maternal cardiac dysfunction/remodeling and that these may be detected by new cardiac biomarkers and maternal echocardiography.

Methods

Prospective cohort study of pregnant women with high-risk of PE in first trimester screening, established diagnosis of PE during gestation, and healthy pregnant women (total intended sample size n = 440). Placental biochemical and biophysical cardiovascular markers will be assessed in the first and third trimesters of pregnancy, along with maternal echocardiographic parameters. Fetal cardiac function at third trimester of pregnancy will be also evaluated and correlated with maternal variables. Maternal cardiac function assessment will be determined 12 months after delivery, and correlation with CV and PE risk variables obtained during pregnancy will be evaluated.

Discussion

The study will contribute to characterize the relationship between anti-angiogenic environment and maternal CV dysfunction/remodeling, during and after pregnancy, as well as its impact on future CVD risk in patients with PE. The ultimate goal is to improve CV health of women with high-risk or previous PE, and thus, reduce the burden of the disease.

Trial registration

NCT04162236

Cardiac Complications in Pregnancy: A Systematic Review and Meta-Analysis of Diagnostic Accuracy of BNP and N-Terminal Pro-BNP

Introduction

Serum brain-type natriuretic peptide (BNP) levels may be involved in detecting the breakdown of defense mechanisms in pregnant women. BNP and N-terminal pro-BNP (NT-proBNP) levels can be used in emergency settings as a biomarker to rule out or confirm cardiac complications. The present study was conducted as an attempt to evaluate the performance of BNP and NT-proBNP as diagnostic tools for cardiac complications, including heart failure and pre-eclampsia, in pregnant and recently-delivered women.

Methods

This meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. To extract the data, articles meeting the inclusion criteria were directly reviewed by two of the authors. Disputes were resolved through discussion with all authors before data mining. In cases of unresolved disagreement, a third reviewer was consulted to achieve consensus. A quantitative analysis of the total bias of publications was performed using Stata software version 14.0, using funnel plots and Deek’s test.

Results

Overall, 13 unique studies were included in this review. The pooled sensitivity, specificity and positive and negative predictive values for diagnosing cardiac complications in pregnant women when BNP level was ≤ 100 ng/L, were determined to be 95, 62, 71 and 91%, respectively. The corresponding measures when the BNP levels were 100–500 ng/L were calculated to be 98, 92, 97 and 92%, respectively. The pooled sensitivity, specificity and positive and negative predictive values for diagnosing cardiac complications in pregnant women using NT-proBNP were 78, 74, 20.5 and 97%, respectively.

Conclusion

Our results suggest that both BNP and NT-proBNP levels can be used as diagnostic tools among pregnant and newly-delivered women to diagnose cardiac complications, including heart failure and pre-eclampsia. While BNP showed a relatively better diagnostic accuracy compared to NT-proBNP, it must be noted that the number of studies evaluating NT-proBNP included in this meta-analysis was low and the studies were inconsistent in terms of cutoff value. Further studies are required to confirm the prospective use of BNP and NT-pro BNP in assessing common symptoms that indicate cardiac complications during labor. Moreover, the clinical use of the NT-proBNP test in this field requires further study.

A more accurate prediction to rule in and rule out pre-eclampsia using the sFlt-1/PlGF ratio and NT-proBNP as biomarkers

Background The management of potential pre-eclamptic patients using the soluble FMS-like tyrosine kinase 1 (sFlt-1)/ placental growth factor (PlGF) ratio is characterised by frequent false-positive results. Methods A retrospective cohort study was conducted to identify and validate cut-off values, obtained using a machine learning model, for the sFlt-1/PlGF ratio and NT-proBNP that would be predictive of the absence or presence of early-onset pre-eclampsia (PE) in singleton pregnancies presenting at 24 to 33 + 6 weeks of gestation. Results For the development cohort, we defined two sFlt-1/PlGF ratio cut-off values of 23 and 45 to rule out and rule in early-onset PE at any time between 24 and 33 + 6 weeks of gestation. Using an sFlt-1/PlGF ratio cut-off value of 23, the negative predictive value (NPV) for the development of early-onset PE was 100% (95% confidence interval [CI]: 99.5-100). The positive predictive value (PPV) of an sFlt-1/PlGF ratio >45 for a diagnosis of early-onset PE was 49.5% (95% CI: 45.8-55.6). When an NT-proBNP value >174 was combined with an sFlt-1/PlGF ratio >45, the PPV was 86% (95% CI: 79.2-92.6). In the validation cohort, the negative and positive values were very similar to those found for the development cohort. Conclusions An sFlt-1/PlGF ratio <23 rules out early-onset PE between 24 and 33 + 6 weeks of gestation at any time, with an NPV of 100%. An sFlt-1/PlGF ratio >45 with an NT-proBNP value >174 significantly enhances the probability of developing early-onset PE.

Is ProBNP a New Marker for Predicting Intrauterine Growth Restriction?

PURPOSE

To evaluate the usability of first-trimester maternal serum ProBNP levels in the prediction of intrauterine growth restriction (IUGR). Methods In this prospective study, blood samples taken from 500 women who applied to our polyclinic for routine serum aneuploidy screening between the 11-14th gestational weeks were centrifuged. The obtained plasma samples were placed in Eppendorf tubes and stored at -80+°C. For the final analysis, first-trimester maternal serum ProBNP levels of 32 women diagnosed with postpartum IUGR and 32 healthy women randomly selected as the control group were compared. FGR was defined as estimated fetal weight below the 10th percentile for the gestational age.

RESULTS

The mean ProBNP levels were statistically and significantly higher in the women with intrauterine growth restriction (113.73±94.69 vs. 58.33±47.70 pg/mL, p<0.01). At a cut-off level of 50.93, ProBNP accurately predicted occurrence of IUGR (AUC+= 0.794 (95% confidence interval 0.679-0.910), p+= 0.001) with sensitivity and specificity rates of 78.1 and 69.0%, respectively. Conclusion First-trimester serum ProBNP level was significantly higher in women who developed IUGR compared to healthy controls. First-trimester ProBNP level can be used as a potential marker to predict the development of IUGR in pregnant women.

NT-proBNP levels in preeclampsia, intrauterine growth restriction as well as in the prediction on an imminent delivery

OBJECTIVES

Studies of cardiovascular function in pregnancy have shown inconsistent and, in some cases, contradictory results, particularly regarding cardiac output. While some studies report preeclampsia associated with high cardiac output, other studies suggest that preeclampsia should be further subdivided into women with high or low cardiac output. This study was conducted to examine the NT-proBNP levels in preeclampsia, intrauterine growth restriction, and hypertensive pregnancies without preeclampsia. We also examined N-terminal pro-B natriuretic peptide (NT-proBNP) levels three to four months after delivery, in preeclamptic women as well as the prediction of delivery within 10 days. In a reduced number of preeclamptic women and controls we performed echocardiograms to study their diastolic function.

METHODS

We investigated the NT-proBNP levels in 213 subjects with preeclampsia only, 73 with intrauterine growth restriction, 44 with preeclampsia and intrauterine growth restriction, 211 who were hypertensive and 662 unaffected pregnancies (controls). We also performed echocardiograms on 36 preeclampsia and 19 controls before delivery and three to five months after delivery.

RESULTS

NT-proBNP levels are higher in early onset preeclampsia than in late onset preeclampsia. Intrauterine growth restriction pregnancies showed a NT-proBNP levels similar to hypertensive and unaffected pregnancies. Compared with healthy pregnancies, women with preterm preeclampsia (<37 gestational weeks) had altered left atrial segments.

CONCLUSIONS

We observed that NT-proBNP levels are higher in early onset preeclampsia than in late onset. Moreover, diastolic dysfunction is higher in early onset than in late-onset term preeclampsia. An NT-proBNP value >136 pg/mL has a high positive predictive value for an imminent delivery within 10 days.

Relevance of the assessment of natriuretic peptide plasma concentrations in hypertensive pregnant women

Assessment of the plasma concentrations of natriuretic peptides (NPs) is widely used to diagnose and evaluate the progression of cardiac failure, and their potential as markers of preeclampsia (PE) has been examined in recent years. It has been established that plasma concentrations of NPs do not change in the course of normal pregnancy. However, elevated levels of these peptides may have a prognostic value in patients with PE. This study presents information about the relevance of NPs assessment in the evaluation of physiological pregnancy, as well as in pregnancy complicated with arterial hypertension. The most commonly examined NPs is the N-terminal fragment of the brain natriuretic peptide (NT-proBNP), and it may be prognostic marker of PE and other complications of pregnancy.

Adaptations in autonomic nervous system regulation in normal and hypertensive pregnancy

There is an increase in basal sympathetic nerve activity (SNA) during normal pregnancy; this counteracts profound primary vasodilation. However, pregnancy also impairs baroreflex control of heart rate and SNA, contributing to increased mortality secondary to peripartum hemorrhage. Pregnancy-induced hypertensive disorders evoke even greater elevations in SNA, which likely contribute to the hypertension. Information concerning mechanisms is limited. In normal pregnancy, increased angiotensin II acts centrally to support elevated SNA. Hypothalamic sites, including the subfornical organ, paraventricular nucleus, and arcuate nucleus, are likely (but unproven) targets. Moreover, no definitive mechanisms for exaggerated sympathoexcitation in hypertensive pregnancy have been identified. In addition, normal pregnancy increases gamma aminobutyric acid inhibition of the rostral ventrolateral medulla (RVLM), a key brainstem site that transmits excitatory inputs to spinal sympathetic preganglionic neurons. Accumulated evidence supports a major role for locally increased production and actions of the neurosteroid allopregnanolone as one mechanism. A consequence is suppression of baroreflex function, but increased basal SNA indicates that excitatory influences predominate in the RVLM. However, many questions remain regarding other sites and factors that support increased SNA during normal pregnancy and, more importantly, the mechanisms underlying excessive sympathoexcitation in life-threatening hypertensive pregnancy disorders such as preeclampsia.

Prediction of Preeclampsia in Nulliparous Women according to First Trimester Maternal Factors and Serum Markers

OBJECTIVE

To evaluate the performance of maternal risk factors (BMI and mean arterial pressure [MAP]) and first-trimester maternal serum markers in the early prediction of preeclampsia (PE) in nulliparous women.

MATERIAL AND METHODS

This was a case-cohort study based on a cohort of 14,207 nulliparous women. A total of 213 cases with term PE (from 37 weeks + 0 days) and 55 cases with preterm PE (before 37 weeks + 0 days) were identified and validated. Randomly, 449 controls were selected. Serum samples previously collected for the double test (pregnancy-associated plasma protein A [PAPP-A] and free β human chorionic gonadotrophin [hCGβ]) as part of the first-trimester screening program were retrieved and analyzed for placental growth factor (PlGF), soluble fms-like tyrosine kinase 1 (sFlt-1), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and neutrophil gelatinase-associated lipocalin (NGAL). Concentrations were transformed to multiples of the median (MoM). Multivariate regression analysis was used for prediction models. Receiver-operating characteristics (ROC) curves were used for evaluation of the screening performance.

RESULTS

In preterm PE, the PlGF (0.79 MoM), sFlt-1 (0.86 MoM), NGAL (1.15 MoM), and PAPP-A (0.89 MoM) medians were significantly altered. In term PE, PlGF (0.90 MoM) and NT-proBNP (0.86 MoM) medians were significantly reduced. The combination of MAP and PlGF yielded a 39% detection rate of preterm PE for a 10% false-positive rate. The combination of MAP, BMI, and PlGF yielded a 33% detection rate of term PE with a 10% false-positive rate.

CONCLUSION

First-trimester MAP, maternal serum PlGF, and NGAL are markers of preterm PE. Maternal serum sFlt-1 is a significant marker of preterm PE, but only early in the first trimester. First-trimester maternal serum NT-proBNP is not a predictor of PE. Screening performance for PE with these markers individually or in combination is modest.

Methods and considerations concerning cardiac output measurement in pregnant women: recommendations of the International Working Group on Maternal Hemodynamics

Cardiac output (CO), along with blood pressure and vascular resistance, is one of the most important parameters of maternal hemodynamic function. Substantial changes in CO occur in normal pregnancy and in most obstetric complications. With the development of several non-invasive techniques for the measurement of CO, there is a growing interest in the determination of this parameter in pregnancy. These techniques were initially developed for use in critical-care settings and were subsequently adopted in obstetrics, often without appropriate validation for use in pregnancy. In this article, methods and devices for the measurement of CO are described and compared, and recommendations are formulated for their use in pregnancy, with the aim of standardizing the assessment of CO and peripheral vascular resistance in clinical practice and research studies on maternal hemodynamics. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Accuracy and precision of USCOM versus transthoracic echocardiography before and during pregnancy

OBJECTIVE

Monitoring hemodynamic status throughout pregnancy may help in identifying women with maladaptation predisposing to hypertensive complications. The Ultrasonic Cardiac Output Monitor (USCOM) is an easy-to-operate device for measuring cardiac output (CO) quickly. Our aim was to assess agreement between USCOM and transthoracic echocardiography (TTE) in: 1) non-pregnant women to correct for possible sources of discrepancy; 2) women longitudinally over the course of the pregnancy.

STUDY DESIGN

High-risk women admitted for cardiovascular risk factor evaluation before pregnancy and multiple times during pregnancy, were included. CO was measured by TTE directly followed by USCOM measurements.

MAIN OUTCOME MEASURES

Bias, limits of agreement (LOA) and percentage error between the two methods by Bland-Altman analysis.

RESULTS

Despite comparable non-pregnant CO levels (4.6 L/min), LOA and percentage error between the two methods improved moderately by optimizing the measurements using only the highest quality USCOM recordings in 132 non-pregnant women (percentage error of 39% and 30%, respectively). During pregnancy, in total 83, 106, 96 and 77 measurements were evaluated at respectively 12, 16, 20 and 30 weeks gestational age. Mean CO in USCOM was about 0.6 L/min higher compared to TTE in all trimesters; percentage error ranged from 35% to 45%. Linear mixed model analysis showed no association between bias and moment of measurement.

CONCLUSION

Agreement between USCOM and TTE in pregnancy was outside our a priori determined level of acceptability and therefore absolute values of USCOM and TTE cannot be used interchangeably. Future research should focus on the agreement of USCOM and TTE in clinical decision-making.

Sex-Related Aspects of Biomarkers in Cardiac Disease

Biomarkers play an important role in the clinical management of cardiac care. In particular, cardiac troponins (cTn) and natriuretic peptides are the cornerstones for the diagnosis of acute myocardial infarction (AMI) and for the diagnosis of heart failure (HF), respectively. Current guidelines do not make a distinction between women and men. However, the commonly used "one size fits all" algorithms are topic of debate to improve assessment of prognosis, particularly in women. Due to the high-sensitivity assays (hs-cTn), lower cTn levels (and 99th percentile upper reference limits) were observed in women as compared with men. Sex-specific diagnostic thresholds may improve the diagnosis of AMI in women, though clinical relevance remains controversial and more trials are needed. Also other diagnostic aspects are under investigation, like combined biomarkers approach and rapid measurement strategies. For the natriuretic peptides, previous studies observed higher concentrations in women than in men, especially in premenopausal women who might benefit from the cardioprotective actions. Contrary to hs-cTn, natriuretic peptides are particularly incorporated in the ruling-out algorithms for the diagnosis of HF and not ruling-in. Clinical relevance of sex differences here seems marginal, as clinical research has shown that negative predictive values for ruling-out HF were hardly effected when applying a universal diagnostic threshold that is independent from sex or other risk factors. Apart from the diagnostic issues of AMI in women, we believe that in the future most sex-specific benefits of cardiac biomarkers can be obtained in patient follow-up (guiding therapy) and prognostic applications, fitting modern ideas on preventive and personalized medicine.