Maternal cardiac function at 35-37 weeks' gestation: prediction of pre-eclampsia and gestational hypertension

Use of the USCOM® noninvasive cardiac output measurement system to predict the development of pre-eclampsia in hypertensive pregnancies

OBJECTIVES

To assess the ability of the USCOM® (USCOM), using measurements of cardiac output (CO) and systemic vascular resistance (SVR), to predict the development of pre-eclampsia (PE) and severe PE in hypertensive pregnancies.

STUDY DESIGN

Prospective cohort study of women in the second or third trimester recruited at a tertiary center in Sydney, Australia. Demographic data and hemodynamic measurements using the USCOM were taken for all study participants at recruitment. Pregnancy outcome, including development of PE and severe PE, was tracked. Data were analyzed using ANOVA testing, pair-wise comparison testing, and Student's t-testing.

RESULTS

Recruitment included 65 normotensive controls, 34 women with chronic hypertension (CH), 51 with gestational hypertension (GH), and 21 with PE. Significantly higher weight, body surface area, and blood pressure measurements were found in the hypertensive, compared with the normotensive control and pregnancies. There were no observed differences in USCOM-measured CO, cardiac index, SVR, or systemic vascular resistance index between hypertensive women who did versus did not develop PE or severe PE in later pregnancy. Analysis of the CH and GH subgroups, as well as only unmedicated hypertensive women (n = 24), also showed no significant difference in hemodynamic parameters between those who did or did not develop PE or severe PE.

CONCLUSIONS

Our group was unable to successfully predict the onset of PE or severe PE based on hemodynamic parameters measured with the USCOM. It is possible this relates to the high proportion of women on antihypertensive medication at recruitment.

Third-Trimester Cardiovascular Function and Risk of Hypertensive Disorders of Pregnancy

BACKGROUND

Whether cardiovascular dysfunction is associated with preeclampsia in women without fetal growth restriction (FGR) is unclear. Our objective was to investigate associations between third-trimester cardiac output (CO) and systemic vascular resistance and risk of hypertensive disorders of pregnancy in women with and without FGR.

METHODS AND RESULTS

A case-cohort study in 906 pregnant women in Denmark with repeated third-trimester cardiac function assessments was performed using the Ultrasound Cardiac Output Monitor 1A. Using Cox regression, we compared rates of hypertensive disorders of pregnancy in women with low, normal, and high CO and normal and high systemic vascular resistance, by FGR status and gestational age, and evaluated associations between a third-trimester drop in CO or increase in systemic vascular resistance and preeclampsia risk in women without FGR. The analysis included 249 women with preeclampsia (42 with FGR) and 119 women with gestational hypertension. Low CO was strongly associated with preeclampsia at <37 weeks (women with FGR: hazard ratio [HR], 5.25 [95% CI, 1.26-21.9]; women without FGR: HR, 2.19 [95% CI, 1.07-4.48]). Our results also suggested an association between low CO and preeclampsia at ≥37 weeks among women without FGR (HR, 1.31 [95% CI, 0.84-2.03]), and between a third-trimester drop in CO >75th percentile and preeclampsia in women without FGR (odds ratio, 1.91 [95% CI, 0.84-4.36]). High systemic vascular resistance was strongly associated with increased rates of all forms of hypertensive disorders of pregnancy.

CONCLUSIONS

Low CO is associated with preeclampsia risk in women with and without FGR, particularly before 37 weeks. Repeated measurements of third-trimester cardiovascular function might identify women without FGR for monitoring for preeclampsia, but this result needs to be confirmed in other studies.

Machine Learning Algorithms Versus Classical Regression Models in Pre-Eclampsia Prediction: A Systematic Review

PURPOSE OF REVIEW

Machine learning (ML) approaches are an emerging alternative for healthcare risk prediction. We aimed to synthesise the literature on ML and classical regression studies exploring potential prognostic factors and to compare prediction performance for pre-eclampsia.

RECENT FINDINGS

From 9382 studies retrieved, 82 were included. Sixty-six publications exclusively reported eighty-four classical regression models to predict variable timing of onset of pre-eclampsia. Another six publications reported purely ML algorithms, whilst another 10 publications reported ML algorithms and classical regression models in the same sample with 8 of 10 findings that ML algorithms outperformed classical regression models. The most frequent prognostic factors were age, pre-pregnancy body mass index, chronic medical conditions, parity, prior history of pre-eclampsia, mean arterial pressure, uterine artery pulsatility index, placental growth factor, and pregnancy-associated plasma protein A. Top performing ML algorithms were random forest (area under the curve (AUC) = 0.94, 95% confidence interval (CI) 0.91-0.96) and extreme gradient boosting (AUC = 0.92, 95% CI 0.90-0.94). The competing risk model had similar performance (AUC = 0.92, 95% CI 0.91-0.92) compared with a neural network. Calibration performance was not reported in the majority of publications. ML algorithms had better performance compared to classical regression models in pre-eclampsia prediction. Random forest and boosting-type algorithms had the best prediction performance. Further research should focus on comparing ML algorithms to classical regression models using the same samples and evaluation metrics to gain insight into their performance. External validation of ML algorithms is warranted to gain insights into their generalisability.

Longitudinal maternal cardiac function in hypertensive disorders of pregnancy

BACKGROUND

Compared with gestational hypertension, preeclampsia has traditionally been considered the worse end of the spectrum of hypertensive disorders of pregnancy. It is associated with worse pregnancy outcomes and future cardiovascular morbidities. Both hypertensive disorders may be associated with cardiac maladaptation in pregnancy. However, previous studies were limited by small numbers and a paucity of longitudinal data and unaccounted for the contribution of maternal characteristics that can affect hemodynamics.

OBJECTIVE

This study aimed to assess, in an unselected population, the maternal cardiac adaptation in normotensive and hypertensive pregnancies after controlling for important maternal characteristics that affect maternal cardiac function and the interaction among these covariates.

STUDY DESIGN

This was a prospective, multicenter longitudinal study of maternal hemodynamics, assessed by a noninvasive bioreactance technology, measured at 11 0/7 to 13 6/7, 19 0/7 to 24 0/7, 30 0/7 to 34 0/7, and 35 0/7 to 37 0/7 weeks of gestation in 3 groups of women. Group 1 was composed of women with preeclampsia (n=45), group 2 was composed of women with gestational hypertension (n=61), and group 3 was composed of normotensive women (n=1643). A multilevel linear mixed-effects model was performed to compare the repeated measures of hemodynamic variables controlling for maternal age, height, weight, weight gain, race, previous obstetrical history, and birthweight.

RESULTS

After adjusting for confounders that significantly affect maternal hemodynamics, both group 1 and group 2, compared with group 3, had pathologic cardiac adaptation. Group 1, compared with group 3, demonstrated hyperdynamic circulation with significantly higher cardiac output driven by greater stroke volume in the first trimester of pregnancy. As the pregnancies progressed to after 20 0/7 weeks of gestation, this hyperdynamic state transitioned to hypodynamic state with low cardiac output and high peripheral vascular resistance. Group 2, compared with group 3, had no significant differences in cardiac output, stroke volume, and heart rate before 20 0/7 weeks of gestation but thereafter demonstrated a continuous decline in cardiac output and stroke volume, similar to group 1. Both groups 1 and 2, compared with group 3, had persistently elevated mean arterial pressure and uterine artery pulsatility index throughout pregnancy.

CONCLUSION

After adjusting for confounders that affect maternal hemodynamics in an unselected pregnant population, women with preeclampsia and gestational hypertension, compared with normotensive women, demonstrated similar cardiac maladaptation. This pathologic profile was evident after 20 0/7 weeks of gestation and at least 10 weeks before the clinical manifestation of the disease.

Impact of maternal height, weight at presentation and gestational weight gain on cardiac adaptation in pregnancy

OBJECTIVE

To compare longitudinal maternal hemodynamic changes throughout gestation between different groups stratified according to weight at presentation and assess the relative influence of height, weight at presentation and gestational weight gain on cardiac adaptation.

METHODS

This was a prospective, longitudinal study assessing maternal hemodynamics using bioreactance technology at 11 + 0 to 13 + 6, 19 + 0 to 24 + 0, 30 + 0 to 34 + 0 and 35 + 0 to 37 + 0 weeks' gestation. Women were divided into three groups according to maternal weight at presentation at the first visit at 11 + 0 to 13 + 6 weeks: Group 1, &lt; 60.0 kg (n = 421); Group 2, 60.0-79.7 kg (n = 904); Group 3, &gt; 79.7 kg (n = 427). A multilevel linear mixed-effects model was used to compare the repeated measures of hemodynamic variables, correcting for demographics, medical and obstetric history, pregnancy complications, maternal weight and time of evaluation. The linear mixed-effects model was then repeated using maternal height, weight at presentation and gestational weight gain Z-scores, and the standardized coefficients were used to evaluate the relative impact of each of these demographic parameters on longitudinal changes of maternal hemodynamics.

RESULTS

Compared with Group 1, women in Group 3 demonstrated higher cardiac output (CO), heart rate (HR) and mean arterial pressure (MAP) throughout pregnancy. Groups 2 and 3 had higher stroke volume (SV) than Group 1 at the first visit, but their SV plateaued between the first and second visits and demonstrated an earlier significant decrease from the second visit to the third visit when compared with Group 1. Compared with Groups 1 and 2, there was a higher prevalence of pre-eclampsia, gestational hypertension and gestational diabetes in Group 3. Maternal height was the most important contributor to CO, peripheral vascular resistance (PVR), SV and HR, while weight at presentation was the most important contributor to MAP. Gestational weight gain was the second most important characteristic influencing the longitudinal changes of PVR and SV.

CONCLUSIONS

Women with greater weight at presentation have a pathological hemodynamic profile, with higher CO, HR and MAP compared to women with lower weight at presentation. Height is the main determinant of CO, SV, HR and PVR, weight is the main determinant of MAP, and gestational weight gain is the second most important determinant of SV and PVR. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Renal and cardiovascular repercussions in preeclampsia and their impact on fluid management: a literature review

Preeclampsia is a multifactorial condition associated with significant morbidity and mortality. Fluid therapy in these patients is challenging since volume expansion may precipitate pulmonary edema, and fluid restriction may worsen renal function. Furthermore, cardiac impairment may introduce an additional component to the hemodynamic management. This article reviews the repercussions of preeclampsia on renal and cardiovascular systems and the development of pulmonary edema, as well as to discuss fluid management, focusing on the mitigation of adverse outcomes and monitoring alternatives. The literature review was carried out using PubMed, Embase, and Google Scholar databases from May 2019 to March 2020. Papers addressing the subjects of interest were included regardless of the publication language. There is a current trend towards restricting the administration of fluids in women with non-complicated preeclampsia. However, patients with preeclampsia may experience hemorrhagic shock, requiring volume resuscitation. In this case, hemodynamic monitoring is recommended to guide fluid therapy while avoiding complications.

Pregnancy complications in chronic hypertensive patients are linked to pre-pregnancy maternal cardiac function and structure

BACKGROUND

Chronic hypertension complicates around 3% of all pregnancies and is associated with an increased risk for pregnancy complications such as superimposed preeclampsia, fetal growth restriction, preterm delivery, and stillbirth, reaching a rate of complications of up to 25-28%.

OBJECTIVE

We performed an echocardiographic study to evaluate pre-pregnancy cardiac geometry and function, along with the hemodynamic features of treated chronic hypertension patients, searching for a possible correlation with the development of feto-maternal complications and with pre-pregnancy therapy.

MATERIALS AND METHODS

This was a prospective observational cohort study of 192 consecutive patients receiving treatment for chronic hypertension (calcium channel blockers, angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, β-blockers, α1-adrenoceptor antagonists, and/or diuretics). Patients underwent echocardiography before pregnancy, assessing left ventricular morphology and function, cardiac output, and total vascular resistance. Pre-pregnancy therapy was noted, patients were shifted to α-methyldopa right before pregnancy, and were followed until delivery, noting major early (<34weeks' gestation) and late (≥34 weeks' gestation) complications. Comparisons among the 3 groups (ie, those with no complications, early complications, and late complications) were performed with 1-way analysis of variance with Student-Newman-Keuls correction for multiple comparisons. The Mann-Whitney U test was used for non-normally distributed data. Comparison of proportions was used as appropriate. Receiver operating characteristic curve analysis was used to identify cutoff values of diastolic dysfunction in this population using the E/e' ratio, and separate cutoff of values for total vascular resistance for the prediction of early and late complications of pregnancy. Binary univariate and multivariate logistic regression as well as Cox proportional hazards regression were used to evaluate the possible correlation among angiotensin-converting enzyme inhibitor/angiotensin receptor blocker and/or calcium channel blocker pre-pregnancy therapy, cardiovascular features, and the risk for subsequent early and late complications of pregnancy.

RESULTS

Of 192 patients, 141 had no complications, and 51 had a complicated pregnancy (24 had early complications and 27 had late complications). Concentric geometry was more frequent in those women with early versus late and no complications (50% vs 13.5% and 11.1%, respectively; P < .05), whereas eccentric hypertrophy was more represented in women with late versus early and no complications (32% versus 12.5% and 1.4%, respectively; P < .05). The receiver operating characteristic curve showed an E/e' ratio value >7.65 (sensitivity, 59.6%; specificity, 68.6%) as a predictor of subsequent complications of pregnancy, whereas total vascular resistance <1048 (sensitivity, 83.7%; specificity, 55.6%) was predictive for late complications and total vascular resistance >1498 (sensitivity, 87.5%; specificity, 78.0%) for the early complications of pregnancy. Univariate analysis showed that the following parameters were predictive for complications of pregnancy: altered geometry of the left ventricle (odds ratio, 5.94; 95% confidence interval, 2.90-12.19), diastolic dysfunction (odds ratio, 3.22; 95% confidence interval, 1.63-6.37), altered total vascular resistance (odds ratio, 3.52; 95% confidence interval, 1.78-6.97), and pre-pregnancy therapy without calcium channel blockers/angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (odds ratio, 2.73; 95% confidence interval, 1.37-5.42). These parameters, except for altered total vascular resistance, were independent predictors in the multivariate analysis corrected for body mass index, heart rate, parity, and mean arterial pressure.

CONCLUSION

Chronic hypertension patients with pre-pregnancy cardiac remodeling and dysfunction more often develop early and late complications of pregnancy. Pre-pregnancy therapy for chronic hypertension patients with calcium channel blockers and/or angiotensin-converting enzyme inhibitors/angiotensin receptor blockers may positively influence cardiac profiles and the outcome of a future pregnancy with a reduced rate of complications.

Maternal Cardiac Assessment at 35 to 37 Weeks Improves Prediction of Development of Preeclampsia

Preeclampsia at term accounts for half of maternal deaths from hypertensive disorders. We aimed to assess differences in maternal cardiac indices at 35⁺⁰ to 36⁺⁶ weeks' gestation between women who subsequently developed preeclampsia at term compared with those with uncomplicated pregnancy and to evaluate whether cardiac indices offer incremental prognostic value to the available screening algorithm for preeclampsia. We recruited 1602 women with singleton pregnancies who attended for a routine hospital visit at 35⁺⁰ to 36⁺⁶ weeks' gestation between April and November 2018. We recorded maternal characteristics and preeclampsia-risk-score derived from a competing risks model and measured cardiac indices. Preeclampsia developed in 3.12% (50/1602) of participants. Women with preeclampsia, compared with those without, had increased mean arterial pressure (97.6, SD, 5.53 versus 87.9, SD, 6.82 mm Hg), systemic vascular resistance (1500, interquartile range, 1393-1831 versus 1400, interquartile range, 1202-1630 PRU) and preeclampsia-risk-score (23.4, interquartile range, 9.13-40 versus 0.9, interquartile range, 0.32-3.25). Multivariable analysis demonstrated independent association between the incidence of preeclampsia and E/e' (hazard ratio, 1.19/unit [95% CI, 1.03-1.37]; P=0.018) as well as left ventricular mass indexed for body surface area (hazard ratio, 1.03/[g·m²] [95% CI, 1.003-1.051]; P=0.029). Women with E/e' ≥7.3 and left ventricular mass indexed for body surface area ≥63.2 g/m² had an increased risk for developing preeclampsia, despite low preeclampsia-risk-score <5% (hazard ratio, 20.1 [95% CI, 10.5-38.7], P<0.001). Increased left ventricular mass and E/e' offer incremental information to available scoring systems and better stratify women at risk of developing preeclampsia at term.

Artificial intelligence-assisted prediction of preeclampsia: Development and external validation of a nationwide health insurance dataset of the BPJS Kesehatan in Indonesia

Background

We developed and validated an artificial intelligence (AI)-assisted prediction of preeclampsia applied to a nationwide health insurance dataset in Indonesia.

Methods

The BPJS Kesehatan dataset have been preprocessed using a nested case-control design into preeclampsia/eclampsia (n = 3318) and normotensive pregnant women (n = 19,883) from all women with one pregnancy. The dataset provided 95 features consisting of demographic variables and medical histories started from 24 months to event and ended by delivery as the event. Six algorithms were compared by area under the receiver operating characteristics curve (AUROC) with a subgroup analysis by time to the event. We compared our model to similar prediction models from systematically reviewed studies. In addition, we conducted a text mining analysis based on natural language processing techniques to interpret our modeling results.

Findings

The best model consisted of 17 predictors extracted by a random forest algorithm. Nine∼12 months to the event was the period that had the best AUROC in external validation by either geographical (0.88, 95% confidence interval (CI) 0.88–0.89) or temporal split (0.86, 95% CI 0.85–0.86). We compared this model to prediction models in seven studies from 869 records in PUBMED, EMBASE, and SCOPUS. This model outperformed the previous models in terms of the precision, sensitivity, and specificity in all validation sets.

Interpretation

Our low-cost model improved preliminary prediction to decide pregnant women that will be predicted by the models with high specificity and advanced predictors.

Funding

This work was supported by grant no. MOST108-2221-E-038-018 from the Ministry of Science and Technology of Taiwan.

Influence of maternal characteristics and gestational age on hemodynamic indices: NICOM device-specific reference ranges

OBJECTIVES

To construct reference ranges for stroke volume, cardiac output and systemic vascular resistance (SVR) in normal pregnancy for the NICOM® device, and to explore associations between maternal characteristics and these hemodynamic variables.

METHODS

This was a prospective cohort study of healthy singleton pregnancies between 10 and 40 weeks' gestation attending a tertiary referral hospital between September 2012 and May 2018. Measurements of stroke volume, cardiac output and SVR were obtained throughout pregnancy using NICOM, a non-invasive device based on bioreactance technology. NICOM device-specific reference ranges were created with respect to gestational age and maternal characteristics. Once the distribution of the data had been determined with respect to the gestational age, patient characteristics were added to the model to test whether they provided a significant improvement in prediction of the median value. The effect was assessed of maternal weight, height, smoking status, conception using assisted reproductive technology, nulliparity and ethnicity.

RESULTS

We included 411 women in this study. The relationships between cardiac variables and gestational age observed in the NICOM-specific reference ranges are consistent with previous findings, with increasing cardiac output values until around 35 weeks and a decrease thereafter until term, and decreasing SVR until around 36 weeks, followed by an increase towards 40 weeks. Stroke volume showed a small linear increase across gestation with lower variability in observations close to term. Maternal weight, height and age were associated with cardiac output (all P < 0.05) and SVR (all P < 0.01), whilst maternal weight and height were associated with stroke volume (both P < 0.001). Ethnicity was significantly associated with stroke volume (P = 0.001) but not with cardiac output or SVR.

CONCLUSIONS

This study presents device-specific reference ranges for stroke volume, cardiac output and SVR for the NICOM device in healthy pregnancy and describes the maternal characteristics that are associated with the values of these hemodynamic measurements. Studies using NICOM in pregnancy can use these ranges in order to evaluate observations relative to those expected in uncomplicated pregnancy conditional on maternal characteristics. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Efficacy and safety of combination of magnesium sulfate, phentolamine and nifedipine in treatment of patients with hypertensive disorder complicating pregnancy

Efficacy and safety of the combination of magnesium sulfate, phentolamine and nifedipine in the treatment of patients with hypertensive disorder complicating pregnancy (HDCP) and its effect on hemodynamics and urinary protein level were investigated. One hundred and six patients with HDCP diagnosed at the Affiliated Hospital of Beihua University from February 5, 2016 to May 9, 2017 were retrospectively analyzed. Patients were divided into the magnesium sulfate group and the combination group, according to the therapeutic schemes. The efficacy 1 week later was observed. The general clinical data of the patients were recorded, and data were acquired with respect to hemodynamic indexes before and after treatment [changes of S/D ratio of umbilical artery flow, and cardiac index and total peripheral resistance (TPR)], the 24-h urinary protein level, clinical efficacy and safety [adverse drug reactions (ADR) and maternal and neonatal outcomes]. Before treatment, there was no statistically significant difference between the two groups in terms of S/D ratio of umbilical artery flow (P>0.05), while after treatment the S/D ratio was significantly lower than that before treatment in both groups (P<0.05). Before treatment, there was no statistically significant difference between the two groups in terms of cardiac index (P>0.05). TPR after treatment was significantly lower than that before treatment in both groups (P<0.001). Compared with the magnesium sulfate group, patients in the combination group had significantly lower 24-h urinary protein level after treatment (P<0.001), significantly higher total effective rate (P<0.05), significantly lower incidence rate of ADR (P<0.001), and significantly lower incidence rate of adverse maternal and neonatal outcomes (P<0.001). In conclusion, the combination of magnesium sulfate, phentolamine and nifedipine can significantly improve the hemodynamic indexes, the 24-h urinary protein level, the clinical efficacy, ADR and maternal and neonatal outcomes of patients with HDCP, therefore it is worthy of use in the clinic.

Correlation between central and uterine hemodynamics in hypertensive disorders of pregnancy

OBJECTIVE

Pregnancies affected by a hypertensive disorder (HDP) have increased uterine artery pulsatility index (UtA-PI) compared with that in healthy pregnancies. Women with HDP are also known to have lower cardiac output and increased systemic vascular resistance. The aim of this study was to investigate the relationship between central and uterine hemodynamics in HDP and uncomplicated pregnancy.

METHODS

This was a prospective study of HDP and normotensive control singleton pregnancies presenting at a tertiary referral hospital between January 2012 and December 2017. Paired measurements of maternal hemodynamics, using a non-invasive device (USCOM-1A®), and UtA-PI were performed in the third trimester. HDP pregnancies were divided into preterm (onset < 37 weeks' gestation) and term (onset ≥ 37 weeks). Spearman's rank coefficient was used to assess the correlation between the central and uteroplacental hemodynamics. Regression analysis was performed to assess the association of UtA-PI with independent variables.

RESULTS

We included 231 women with HDP (152 with preterm and 79 with term HDP) and 378 controls with normotensive pregnancy. Compared with controls, women with preterm HDP had significantly lower cardiac output (median (interquartile range (IQR)), 6.0 (5.1-7.2) vs 6.6 (5.8-7.5) L/min; P < 0.001) and significantly higher systemic vascular resistance (median (IQR), 1394 (1189-1670) vs 1063 (915-1222) dynes × s/cm⁵ ; P < 0.001) and UtA-PI (median (IQR), 1.0 (0.75-1.4) vs 0.67 (0.58-0.83); P < 0.001). Conversely, in women with term HDP, there were no significant differences in heart rate, cardiac output or UtA-PI compared with controls (all P > 0.05), while systemic vascular resistance was significantly higher (median (IQR), 1315 (1099-1527) vs 1063 (915-1222) dynes × s/cm⁵ ; P < 0.001). On multiple regression analysis, heart rate, mean arterial pressure and stroke volume were associated significantly with mean UtA-PI (all P < 0.001).

CONCLUSIONS

Differences observed between HDP and normotensive pregnancies in third-trimester UtA resistance are mirrored in the central maternal hemodynamic parameters. Late pregnancy differences in the uteroplacental circulation in preterm and term HDP are an index of maternal cardiovascular function rather than being related to inadequate spiral artery remodeling and impaired placentation. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Prediction models for preeclampsia: A systematic review

BACKGROUND

Preeclampsia is a disease specific to pregnancy that can cause severe maternal and foetal morbidity and mortality. Early identification of women at higher risk for preeclampsia could potentially aid early prevention and treatment. Although a plethora of preeclampsia prediction models have been developed in recent years, individualised prediction of preeclampsia is rarely used in clinical practice.

OBJECTIVES

The objective of this systematic review was to provide an overview of studies on preeclampsia prediction.

STUDY DESIGN

Relevant research papers were identified through a MEDLINE search up to 1 January 2017. Prognostic studies on the prediction of preeclampsia or preeclampsia-related disorders were included. Quality screening was performed with the Quality in Prognostic Studies (QUIPS) tool.

RESULTS

Sixty-eight prediction models from 70 studies with 425,125 participants were selected for further review. The number of participants varied and the gestational age at prediction varied widely across studies. The most frequently used predictors were medical history, body mass index, blood pressure, parity, uterine artery pulsatility index, and maternal age. The type of predictor (maternal characteristics, ultrasound markers and/or biomarkers) was not clearly associated with model discrimination. Few prediction studies were internally (4%) or externally (6%) validated.

CONCLUSIONS

To date, multiple and widely varying models for preeclampsia prediction have been developed, some yielding promising results. The high degree of between-study heterogeneity impedes selection of the best model, or an aggregated analysis of prognostic models. Before multivariable preeclampsia prediction can be clinically implemented universally, further validation and calibration of well-performing prediction models is needed.

Cardiovascular origins of preeclampsia

PURPOSE OF REVIEW

To review the current data on maternal cardiovascular adaptation in normal pregnancy and preeclampsia.

RECENT FINDINGS

Defective placentation causes early-onset preeclampsia, a disease entity that is considered more or less distinct from late-onset preeclampsia. The latter has been attributed as 'maternal' preeclampsia. There are inconsistencies with the placental origins hypothesis, especially when considering the lack of a causative association with abnormal placental histology or impaired fetal growth. An alternative explanation is that placental dysfunction is secondary to maternal cardiovascular maladaptation in pregnancy. The concept that placental dysfunction is secondary to a maternal disorder is not new when one considers the clinical similarities between preeclampsia and gestational diabetes - both pregnancy-specific conditions that are cured by birth. It is accepted that gestational diabetes develops when the maternal pancreas is unable to manage the increasing glucose load of pregnancy. It is now apparent that pregnancy presents a substantial cardiovascular load on the maternal heart, and that cardiovascular dysfunction precedes the disorder, predominates in the clinical syndrome and persists for several decades postpartum. It is time to consider the evidence that failure of the maternal cardiovascular system to adapt to pregnancy may well be the primary mechanism leading to secondary placental dysfunction in preeclampsia.

SUMMARY

Many of the existing paradoxes of preeclampsia challenge the placental origin hypothesis and are explained if one considered preeclampsia to be a cardiovascular syndrome.

Agreement between preload reserve measured by impedance cardiography and echocardiography during pregnancy

Purpose

Accurate assessment of cardiac function is important during pregnancy. Echocardiography and impedance cardiography (ICG) are commonly used noninvasive methods to measure stroke volume (SV) and cardiac output (CO). The difference in stroke volume (ΔSV) or cardiac output (ΔCO) measured at baseline and after passive leg raising (PLR) is a measure of preload reserve that predicts volume responsiveness. However, the agreement between these two methods in measuring preload reserve during pregnancy is unclear. The aim of our study was to investigate the correlation and the agreement between Doppler echocardiography and ICG in assessing preload reserve in pregnant women.

Methods

In this prospective observational cross-sectional study, preload reserve was assessed by measuring the SV and CO during baseline and 90 s after PLR simultaneously by Doppler echocardiography and ICG in healthy pregnant women during the second and third trimesters. Bland–Altman analysis was used to determine the agreement between the two methods. Bias was calculated as the mean difference between two methods and precision as 1.96 SD of the difference.

Results

A total of 53 pregnant women were included. We found a statistically significant correlation between ΔSV (R = 0.56, p < 0.0001) and ΔCO (R = 0.39, p = 0.004) measured by ICG and Doppler echocardiography. The mean bias for ΔSV was 2.52 ml, with a precision of 18.19 ml. The mean bias for ΔCO was 0.21 l/min, with a precision of 1.51 l/min.

Conclusion

There was a good agreement and a statistically significant correlation between ICG and Doppler echocardiography for measuring preload reserve.

Effect of change in posture on maternal functional hemodynamics at 35-37 weeks' gestation

OBJECTIVES

To evaluate the effect of posture change from the supine to the sitting position and before and after passive leg raising on maternal functional hemodynamics in pregnant women at 35-37 weeks' gestation, and to compare the changes in pregnancies that subsequently developed pre-eclampsia (PE) or gestational hypertension (GH) with those that remained normotensive.

METHODS

In 2764 singleton pregnancies at 35-37 weeks' gestation, maternal cardiovascular parameters were measured using an automated non-invasive cardiac monitor. The hemodynamic response to a change from the supine to the sitting position and before and after passive leg raising in the left lateral position was examined and compared between women who subsequently developed PE or GH and those who remained normotensive.

RESULTS

In normotensive singleton pregnancies at 35-37 weeks' gestation, both change from the supine to the sitting position and passive leg raising were associated with an increase in cardiac index and stroke volume index and a decrease in total peripheral resistance index; there was a small increase in mean arterial pressure with both postural changes and a slight decrease in heart rate with passive leg raising. In pregnancies that subsequently developed PE or GH, compared with normotensive pregnancies, cardiac index and stroke volume index were lower and total peripheral resistance index was higher. In general, change from the supine to the sitting position and passive leg raising were associated with similar but less marked changes in cardiovascular parameters as in normotensive pregnancies.

CONCLUSIONS

Paradoxically, in late third-trimester normal pregnancy, both change from the supine to a sitting position and passive leg raising may result in an increase in preload with a consequent increase in cardiac and stroke volume indices and a decrease in total peripheral resistance index. In pregnancies that develop PE or GH, the effects of postural change on cardiovascular parameters are similar but less marked than in normotensive pregnancies. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Magnesium Sulfate Prevents Placental Ischemia-Induced Increases in Brain Water Content and Cerebrospinal Fluid Cytokines in Pregnant Rats

Magnesium sulfate (MgSO₄) is the most widely used therapy in the clinic to prevent the progression of preeclampsia, a hypertensive disorder of pregnancy, to eclampsia. Eclampsia, manifested as unexplained seizures and/or coma during pregnancy or postpartum, accounts for ~13% of maternal deaths worldwide. While MgSO₄ continues to be used in the clinic, the mechanisms by which it exerts its protective actions are not well understood. In this study, we tested the hypothesis that MgSO₄ protects against placental ischemia-induced increases in brain water content and cerebrospinal fluid cytokines. To test this hypothesis, MgSO₄ was administered via mini-osmotic pump (60 mg/day, i.p.) to pregnant and placental ischemic rats, induced by mechanical reduction of uterine perfusion pressure, from gestational day 14–19. This treatment regimen of MgSO₄ led to therapeutic level of 2.8 ± 0.6 mmol/L Mg in plasma. MgSO₄ had no effect on improving placental ischemia-induced changes in mean arterial pressure, number of live fetuses, or fetal and placental weight. Placental ischemia increased, while MgSO₄ prevented the increase in water content in the anterior cerebrum. Cytokine and chemokine levels were measured in the cerebrospinal fluid using a multi-plex assay. Results demonstrate that cerebrospinal fluid, obtained via the cisterna magna, had reduced protein, albumin, interleukin (IL)-17A, IL-18, IL-2, eotaxin, fractalkine, interferon gamma, vascular endothelial growth factor (VEGF), and macrophage inflammatory protein (MIP)-2 following MgSO₄ treatment. These data support the hypothesis that MgSO₄ offers neuroprotection by preventing placental ischemia-induced cerebral edema and reducing levels of cytokines/chemokines in the cerebrospinal fluid.