Maternal hemodynamics at 11-13 weeks' gestation and risk of pre-eclampsia

Pulse Wave Velocity as a Tool for Cardiometabolic Risk Stratification in Individuals With Hypertensive Disorders of Pregnancy and Increased BMI

OBJECTIVES

Obesity is one of the most prevalent risk factors for hypertensive disorders of pregnancy (HDP); however, the role of pre-pregnancy cardiometabolic health in the development of these conditions is not well understood. Carotid-femoral pulse wave velocity (PWV) is an established measure of arterial stiffness and cardiovascular health and is validated in pregnancy. Our objective was to examine the obesity-related changes in PWV in pregnant individuals with and without HDP.

METHODS

Overall, 87 individuals with singleton pregnancies were recruited and classified into 2 groups: cases (HDP: including pre-existing/chronic hypertension, gestational hypertension, preeclampsia, or intrauterine growth restriction; n = 39) and normotensive controls (no HDP or intrauterine growth restriction; n = 48). Patient data, including BMI, were collected from patient charts. Measurements of PWV were performed weekly until discharge or delivery (gestational age 230-380 weeks) and placental growth factor (PlGF) was measured at routine blood draws.

RESULTS

PWV did not significantly change over gestation for either group. Cases had significantly increased PWV and decreased PlGF compared to normotensive controls. An elevated BMI was associated with higher PWV in both cases and controls. Once grouped based on BMI, PWV was only significantly higher in cases with a BMI ≥25 kg/m2 compared to controls, whereas PlGF was less affected by BMI. As PWV increased, PlGF decreased; however, after controlling for BMI, there was no relationship between PWV and PlGF.

CONCLUSIONS

PWV measurements in early pregnancy may be useful as an additional independent marker to PlGF for risk-stratifying for HDP, especially in individuals with increased BMI.

The Use of Statins During Pregnancy in Patients Diagnosed With Preeclampsia: A Systematic Review

Preeclampsia is a hypertensive disorder of pregnancy characterized by endothelial dysfunction, inflammation, and angiogenic imbalance, contributing to significant global maternal and fetal morbidity. Statins, particularly pravastatin, have shown promise in mitigating preeclampsia through their pleiotropic effects, including upregulation of nitric oxide, reduction of oxidative stress, and improvement of placental vascular function. Recent clinical trials have exhibited pravastatin's safety in pregnancy and efficacy in reducing preterm preeclampsia and improving maternal and neonatal outcomes. Trials such as the StAmP (Statins to Ameliorate Preeclampsia) and INOVASIA (Indonesia Pravastatin to Prevent Preeclampsia Study) and Costantine et al studies highlight pravastatin's favorable safety profile with no significant maternal or fetal adverse effects. While some studies report limited statistical significance in biomarker changes, pravastatin consistently improves neonatal outcomes such as birth weight, Apgar scores, and neonatal intensive care unit stays. These findings support pravastatin as a potential therapeutic option for preeclampsia management. Further larger-scale trials are needed to confirm optimal dosing, long-term safety, and its future role in clinical practice.

Maternal vascular indices at 36 weeks' gestation in the prediction of preeclampsia

BACKGROUND

Epidemiological studies have shown that women with preeclampsia (PE) are at increased long term cardiovascular risk. This risk might be associated with accelerated vascular ageing process but data on vascular abnormalities in women with PE are scarce.

OBJECTIVE

This study aimed to identify the most discriminatory maternal vascular index in the prediction of PE at 35 to 37 weeks' gestation and to examine the performance of screening for PE by combinations of maternal risk factors and biophysical and biochemical markers at 35 to 37 weeks' gestation.

STUDY DESIGN

This was a prospective observational nonintervention study in women attending a routine hospital visit at 35 0/7 to 36 6/7 weeks' gestation. The visit included recording of maternal demographic characteristics and medical history, vascular indices, and hemodynamic parameters obtained by a noninvasive operator-independent device (pulse wave velocity, augmentation index, cardiac output, stroke volume, central systolic and diastolic blood pressures, total peripheral resistance, and fetal heart rate), mean arterial pressure, uterine artery pulsatility index, and serum concentration of placental growth factor and soluble fms-like tyrosine kinase-1. The performance of screening for delivery with PE at any time and at <3 weeks from assessment using a combination of maternal risk factors and various combinations of biomarkers was determined.

RESULTS

The study population consisted of 6746 women with singleton pregnancies, including 176 women (2.6%) who subsequently developed PE. There were 3 main findings. First, in women who developed PE, compared with those who did not, there were higher central systolic and diastolic blood pressures, pulse wave velocity, peripheral vascular resistance, and augmentation index. Second, the most discriminatory indices were systolic and diastolic blood pressures and pulse wave velocity, with poor prediction from the other indices. However, the performance of screening by a combination of maternal risk factors plus mean arterial pressure was at least as high as that of a combination of maternal risk factors plus central systolic and diastolic blood pressures; consequently, in screening for PE, pulse wave velocity, mean arterial pressure, uterine artery pulsatility index, placental growth factor, and soluble fms-like tyrosine kinase-1 were used. Third, in screening for both PE within 3 weeks and PE at any time from assessment, the detection rate at a false-positive rate of 10% of a biophysical test consisting of maternal risk factors plus mean arterial pressure, uterine artery pulsatility index, and pulse wave velocity (PE within 3 weeks: 85.2%; 95% confidence interval, 75.6%-92.1%; PE at any time: 69.9%; 95% confidence interval, 62.5%-76.6%) was not significantly different from a biochemical test using the competing risks model to combine maternal risk factors with placental growth factor and soluble fms-like tyrosine kinase-1 (PE within 3 weeks: 80.2%; 95% confidence interval, 69.9%-88.3%; PE at any time: 64.2%; 95% confidence interval, 56.6%-71.3%), and they were both superior to screening by low placental growth factor concentration (PE within 3 weeks: 53.1%; 95% confidence interval, 41.7%-64.3%; PE at any time: 44.3; 95% confidence interval, 36.8%-52.0%) or high soluble fms-like tyrosine kinase-1-to-placental growth factor concentration ratio (PE within 3 weeks: 65.4%; 95% confidence interval, 54.0%-75.7%; PE at any time: 53.4%; 95% confidence interval, 45.8%-60.9%).

CONCLUSION

First, increased maternal arterial stiffness preceded the clinical onset of PE. Second, maternal pulse wave velocity at 35 to 37 weeks' gestation in combination with mean arterial pressure and uterine artery pulsatility index provided effective prediction of subsequent development of preeclampsia.

A mathematical model of vascular and hemodynamics changes in early and late forms of preeclampsia

Preeclampsia-eclampsia syndrome is a leading cause of maternal mortality. The precise etiology of preeclampsia is still not well-defined and different forms exist, including early and late forms or preeclampsia, which may arise via distinctly different mechanisms. Low-dose aspirin administered at the end of the first trimester in women identified as high risk has been shown to reduce the incidence of early, but not late, preeclampsia; however, current risk factors show only fair predictive capability. There is a pressing need to develop accurate descriptions for the different forms of preeclampsia. This paper presents 1D fluid, solid, growth, and remodeling models for pregnancies complicated with early and late forms of preeclampsia. Simulations affirm a broad set of literature results that early forms of preeclampsia are characterized by elevated uterine artery pulsatility index (UA-PI) and total peripheral resistance (TPR) and lower cardiac output (CO), with modestly increased mean arterial blood pressure (MAP) in the first half of pregnancy, with elevation of TPR and MAP beginning at 20 weeks. Conversely, late forms of preeclampsia are characterized by only slightly elevated UA-PI and normal pre-term TPR, and slightly elevated MAP and CO throughout pregnancy, with increased TPR and MAP beginning after 34 weeks. Results suggest that preexisting arterial stiffness may be elevated in women that develop both early forms and late forms of preeclampsia; however, data that verify these results are lacking in the literature. Pulse wave velocity increases in early- and late-preeclampsia, coincident with increases in blood pressure; however, these increases are mainly due to the strain-stiffening response of larger arteries, rather than arterial remodeling-derived changes in material properties. These simulations affirm that early forms of preeclampsia may be associated with abnormal placentation, whereas late forms may be more closely associated with preexisting maternal cardiovascular factors; simulations also highlight several critical gaps in available data.

Arterial stiffness for the early prediction of pre-eclampsia compared with blood pressure, uterine artery Doppler and angiogenic biomarkers: a prospective cohort study

OBJECTIVE

Our aim was to evaluate the ability of arterial stiffness parameters to predict pre-eclampsia early compared with peripheral blood pressure, uterine artery Doppler and established angiogenic biomarkers.

DESIGN

Prospective cohort study.

SETTING

Tertiary care antenatal clinics in Montreal, Canada.

POPULATION

Women with singleton high-risk pregnancies.

METHODS

In the first trimester, arterial stiffness was measured by applanation tonometry, along with peripheral blood pressure and serum/plasma angiogenic biomarkers; uterine artery Doppler was measured in the second trimester. The predictive ability of different metrics was assessed through multivariate logistic regression.

MAIN OUTCOME MEASURES

Arterial stiffness (carotid-femoral pulse wave velocity, carotid-radial pulse wave velocity) and wave reflection (augmentation index, reflected wave start time), peripheral blood pressure, ultrasound indices of velocimetry and circulating angiogenic biomarker concentrations.

RESULTS

In this prospective study, among 191 high-risk pregnant women, 14 (7.3%) developed pre-eclampsia. A first-trimester 1 m/s increase in carotid-femoral pulse wave velocity was associated with 64% increased odds (P < 0.05), and a 1-millisecond increase in time to wave reflection with 11% decreased odds for pre-eclampsia (P < 0.01). The area under the curve of arterial stiffness, blood pressure, ultrasound indices and angiogenic biomarkers was 0.83 (95% confidence interval [CI] 0.74-0.92), 0.71 (95% CI 0.57-0.86), 0.58 (95% CI 0.39-0.77), and 0.64 (95% CI 0.44-0.83), respectively. With a 5% false-positive rate, blood pressure had a sensitivity of 14% for pre-eclampsia and arterial stiffness a sensitivity of 36%.

CONCLUSIONS

Arterial stiffness predicted pre-eclampsia earlier and with greater ability than blood pressure, ultrasound indices or angiogenic biomarkers.

Role of placental, fetal and maternal cardiovascular markers in predicting adverse outcome in women with suspected or confirmed pre-eclampsia

OBJECTIVE

To assess the performance of placental, fetal and maternal cardiovascular markers in the prediction of adverse perinatal and maternal outcomes in women with suspected or confirmed pre-eclampsia.

METHODS

This was a prospective prognostic accuracy study of women with suspected or confirmed pre-eclampsia who underwent a series of investigations to measure maternal hemodynamic indices, mean arterial pressure, augmentation index, ophthalmic artery peak systolic velocity (PSV) ratio, uterine artery pulsatility index (UtA-PI), fetal biometric and Doppler parameters, soluble fms-like tyrosine kinase-1 (sFlt-1) and placental growth factor (PlGF). The performance of these markers, individually or in combination, in predicting adverse perinatal and maternal outcomes was then assessed using receiver-operating-characteristics (ROC)-curve analysis. Adverse maternal outcome was defined as one or more of severe hypertension, admission to the intensive care unit, eclampsia, placental abruption, HELLP syndrome, disseminated intravascular coagulation, platelets < 100 × 109 /L, creatinine > 90 μmol/L and alanine aminotransferase > 100 U/L. Adverse perinatal outcome was defined as one or more of preterm birth at or before 34 + 0 weeks, neonatal intensive care unit admission for > 48 h, respiratory distress syndrome, intraventricular hemorrhage, hypoxic ischemic encephalopathy, necrotizing enterocolitis, retinopathy of prematurity and confirmed fetal infection.

RESULTS

We recruited 126 women with suspected (n = 31) or confirmed (n = 95) pre-eclampsia at a median gestational age of 33.9 weeks (interquartile range, 30.9-36.3 weeks). Pregnancies with adverse perinatal outcome compared to those without had a higher median UtA-PI (1.3 vs 0.8; P < 0.001), ophthalmic artery PSV ratio (0.8 vs 0.7; P = 0.01) and umbilical artery PI percentile (82.0 vs 68.5; P < 0.01) and lower median estimated fetal weight percentile (4.0 vs 43.0; P < 0.001), abdominal circumference percentile (4.0 vs 63.0; P < 0.001), middle cerebral artery PI percentile (28.0 vs 58.5; P < 0.001) and cerebroplacental ratio percentile (18.0 vs 46.5; P < 0.001). Pregnancies with adverse perinatal outcome also had a higher median sFlt-1 (8208.0 pg/mL vs 4508.0 pg/mL; P < 0.001), lower PlGF (27.2 pg/mL vs 76.3 pg/mL; P < 0.001) and a higher sFlt-1/PlGF ratio (445.4 vs 74.4; P < 0.001). The best performing individual marker for predicting adverse perinatal outcome was the sFlt-1/PlGF ratio (area under the ROC curve (AUC), 0.87 (95% CI, 0.81-0.93)), followed by estimated fetal weight (AUC, 0.81 (95% CI, 0.73-0.89)). Women who experienced adverse maternal outcome had a higher median sFlt-1 level (7471.0 pg/mL vs 5131.0 pg/mL; P < 0.001) and sFlt-1/PlGF ratio (204.3 vs 93.3; P < 0.001) and a lower PlGF level (37.0 pg/mL vs 66.1 pg/mL; P = 0.01) and estimated fetal weight percentile (16.5 vs 37.0; P = 0.04). All markers performed poorly in predicting adverse maternal outcome, with sFlt-1 (AUC, 0.69 (95% CI, 0.60-0.79)) and sFlt-1/PlGF ratio (AUC, 0.69 (95% CI, 0.59-0.78)) demonstrating the best individual performance. The addition of cardiovascular, fetal or other placental indices to the sFlt-1/PlGF ratio did not improve the prediction of adverse maternal or perinatal outcomes.

CONCLUSIONS

The sFlt-1/PlGF ratio performs well in predicting adverse perinatal outcomes but is a poor predictor of adverse maternal outcomes in women with suspected or diagnosed pre-eclampsia. The addition of cardiovascular or fetal indices to the model is unlikely to improve the prognostic performance of the sFlt-1/PlGF ratio. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Blood pressure adjustments throughout healthy and hypertensive pregnancy: A systematic review and meta-analysis

Gestational hypertensive complications are preceded by deviant hemodynamic adjustments affecting blood pressure. Our objective was to determine the timing and magnitude of changes in blood pressure during singleton normotensive and hypertensive pregnancies. PubMed (NCBI) and Embase (Ovid) databases were searched for relevant studies up to November 2019. Studies reporting original blood pressure measurements during pregnancy together with a non-pregnant reference measurement were included. Studies including women with a history of cardiovascular or metabolic disease, or women using antihypertensive drugs were excluded. Pooled mean differences between pregnant and non-pregnant women, and absolute blood pressure values were calculated for predefined gestational intervals in normotensive and hypertensive pregnancy, using a random-effects model. Meta-regression analysis was used to analyze group differences in adjustments. In early normotensive pregnancy, both systolic and diastolic blood pressure decreased, reaching their maximum reduction of -4 mmHg (95%CI -6 to -1 mmHg) and -4 mmHg (95%CI, -5 to -3 mmHg), respectively in the second trimester. Thereafter, blood pressure gradually increased towards non-pregnant values. All absolute blood pressure measurements throughout normotensive pregnancy were below 130/80 mmHg. In hypertensive pregnancies, only diastolic blood pressure decreased early in pregnancy. In conclusion, this meta-analysis showed a clinically moderate, but significant mid-pregnancy drop in blood pressure during normotensive pregnancy. Reference curves with absolute values underscore the current liberal cut-off limit for gestational hypertension. A lack of a mid-pregnancy systolic blood pressure drop might reflect increased vascular resistance in women destined to develop hypertensive pregnancy complications.

Arterial Stiffness as a Cardiovascular Risk Factor for the Development of Preeclampsia and Pharmacopreventive Options

Arterial stiffness (AS) describes the rigidity of the arterial walls. Epidemiological studies have shown that increased AS is an independent predictive marker of cardiovascular (CV) morbidity and mortality in both pregnant and non-pregnant women. Preeclampsia (PE), a form of pregnancy-induced hypertension, affects approximately 5% of pregnancies worldwide. Preeclamptic women have a higher risk of CV disease (CVD), mainly because PE damages the heart's ability to relax between contractions. Different pharmacological approaches for the prevention of PE have been tested in clinical trials (e.g. aspirin, enoxaparin, metformin, pravastatin, and sildenafil citrate). In current clinical practice, only low-dose aspirin is used for PE pharmacoprevention. However, low-dose aspirin does not prevent term PE, which is the most common form of PE. Compromised vascular integrity precedes the onset of PE and therefore, AS assessment may constitute a promising predictive marker of PE. Several non-invasive techniques have been developed to assess AS. Compared with normotensive pregnancies, both carotid-femoral pulse wave velocity (cfPWV) and augmentation index (AIx) are increased in PE. In view of simplicity, reliability, and reproducibility, there is an interest in oscillometric AS measurements in pregnancies complicated by PE.

A longitudinal analysis of arterial stiffness and wave reflection in preeclampsia: Identification of changepoints

PURPOSE

Preeclampsia (PrE) is a leading complication of pregnancy characterized by vascular dysfunction. Characterizing the longitudinal changes in vascular function prior to PrE onset is critical to the identification of optimal timepoints for vascular assessment and the development of effective early screening strategies.

METHODS

In this prospective longitudinal study of women with singleton high-risk pregnancies, arterial stiffness and wave reflection parameters were assessed using applanation tonometry at 10-13 weeks' gestation and repeated every 4 weeks throughout pregnancy. Changepoints in carotid-femoral pulse wave velocity (cfPWV), carotid-radial PWV (crPWV), augmentation index (AIx), time to wave reflection (T_1R), pulse pressure amplification (PPA), and subendocardial viability ratio (SEVR) were compared between women who did and did not subsequently develop PrE.

RESULTS

A changepoint in cfPWV and crPWV was detected at 14-17 weeks' gestation. cfPWV then increased in women who went on to develop PrE but decreased in women who did not; a 1.2 m/s difference in cfPWV between the groups was observed at 22-25 weeks' gestation. Conversely, crPWV converged in the two groups from a baseline difference of 1.05 m/s (95% credible interval: 0.37, 1.72). Women who subsequently developed PrE demonstrated an increase in AIx at 18-21 weeks' gestation that was not seen in women who did not develop PrE until 30-33 weeks. No differences in T_1R, PPA, or SEVR were observed between the groups.

CONCLUSIONS

Altered vascular adaptations were detected using measures of arterial stiffness and wave reflection in the early second trimester of pregnant women who developed PrE compared to those who did not. These findings demonstrate the potential clinical utility of arterial stiffness and wave reflection parameters as an early screening tool for PrE, which can be used to inform clinical management of high-risk pregnancies.

Role of arterial impairment in preeclampsia: should the paradigm shift?

Preeclampsia is a worldwide pregnancy complication with serious short- and long-term maternal and neonatal consequences. Our understanding of preeclampsia pathophysiology has significantly evolved over the last decades with the recognition that impaired arterial function and structure may occur early in the course of pregnancy, preceding the clinic-humoral syndrome and driving long-term cardiovascular disease risk in the future of these patients. Although an early abnormal placentation may be the inciting event for a large proportion of cases, there is growing evidence that challenges the placental hypothesis in all affected women, since placental histopathology lesions thought to be characteristic are neither sensitive nor specific markers for the disorder. Recent hemodynamic investigations and studies on left ventricular function and structure in women with preeclampsia further challenge this universal paradigm and propose that placental dysfunction could be secondary to a maternal cardiovascular maladaptation to pregnancy in certain patients. Supporting this hypothesis, certain vascular features, which are characteristically enhanced in normal pregnancy allowing a healthy vascular adaptation, are absent in preeclampsia and comparable to the nonpregnant population. However, arterial biomechanics in preeclampsia may only not cope with hemodynamic demands of pregnancy but also impose additional detrimental loads to the maternal heart ("impaired left-ventricle-aorta coupling") and transmit pressure and flow disturbances into the fetoplacental circulation ("impaired large arteries-microcirculation coupling"). In this review, we analyze the major role of the arterial dysfunction in the cardiovascular maladaptation hypothesis of preeclampsia, shed light on its potential etiopathogenic link, and discuss the complementary nature of the placental and cardiovascular theories.

Maternal arterial stiffness in hypertensive pregnancies with and without small-for-gestational-age neonate

OBJECTIVE

Pregnancies complicated by pre-eclampsia with a small-for-gestational-age (SGA) neonate have poorer maternal hemodynamic function compared to those with hypertensive disorders of pregnancy (HDP) and an appropriately grown neonate. Arterial stiffness is a recognized prognostic marker of cardiovascular disease in the general population. The aim of this study was to compare maternal arterial stiffness between hypertensive pregnancies with, and those without, a SGA neonate and normotensive control pregnancies.

METHODS

This was a prospective cohort study of pregnancies complicated by pre-eclampsia or gestational hypertension and healthy normotensive control pregnancies, presenting to a tertiary referral hospital between January 2012 and May 2018. Maternal arterial stiffness was assessed by aortic pulse-wave velocity (PWV) and aortic augmentation index (AIx), which were recorded using a non-invasive device (Arteriograph®). Maternal and hemodynamic factors were adjusted for using linear regression analysis. Pregnancies with HDP were divided into those that delivered a SGA (birth weight < 10^th percentile) neonate (HDP + SGA group) and those that delivered an appropriately grown neonate (HDP-only group). Comparisons between groups were carried out using the Mann-Whitney U-test for continuous variables and the chi-square (or Fisher's exact) test for categorical variables.

RESULTS

Included in the analysis were 69 patients with HDP who delivered a SGA neonate, 129 with HDP who delivered a normally grown neonate and 220 healthy controls. Maternal age, weight, height and heart rate were associated significantly with brachial and aortic AIx. Maternal weight, height, mean arterial pressure, heart rate and gestational age were significant predictors of aortic PWV. Adjusted aortic AIx was significantly higher in both the HDP + SGA and HDP-only groups, compared with in controls (12.5% and 10.0% vs 7.6%; both P < 0.01), and was significantly different between the two HDP groups (P = 0.002). Adjusted PWV was significantly higher in the HDP-only group compared with in controls and the HDP + SGA group (7.7 m/s vs 7.1 m/s and 7.1 m/s; both P < 0.001). Conversely, unadjusted PWV was not significantly different between the two HDP groups (P = 0.414).

CONCLUSIONS

Pregnancies complicated by HDP with, and those without, a SGA neonate have significantly higher aortic AIx compared with uncomplicated normotensive pregnancies. Aortic AIx was highest in those pregnancies complicated by HDP with a SGA neonate, reflecting a progression in severity of arterial stiffness abnormality with a worsening clinical picture. These findings most likely reflect systemic reduced vascular compliance and increased systemic vascular resistance in pregnancy complicated by HDP. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Arterial Function in Healthy Pregnant Women vs. Non-Pregnant Women-A 10-Year Study

INTRODUCTION

Maternal age for the first pregnancy is increasing and so, the prevalence of cardiovascular risk factors in pregnancy is also increasing. Heart disease is the main reason for maternal death during pregnancy in developed countries. Arterial stiffness is an independent risk factor for atherosclerosis and a predictor of cardiovascular morbidity and mortality. The most widespread parameters for detecting subclinical atherosclerosis are augmentation index (AIx) and pulse wave velocity (PWV). The objective of this prospective study was to assess the differences between arterial function in pregnant vs. non-pregnant women of the same age, and its changes throughout the gestation period.

MATERIALS AND METHODS

Between 2010-2019, 887 patients were enrolled into 2 groups: pregnant (N1 = 471) and non-pregnant (N2 = 416). Data about their anthropometric characteristics, arterial function (for group 1 in all three trimesters and 6 weeks post-partum), smoking status and physical activity were collected.

RESULTS

There were statistically significant differences (p < α, α = 0.05) between the two groups regarding the body mass index, brachial AIx, systolic, diastolic and central blood pressure, and pulse pressure values. In the first group, there was a decrease of both brachial AIx and PWV in the second and third trimester, followed by a post-partum increase; better outcomes were noticed in physically active women.

CONCLUSIONS

Arterial function modifies during pregnancy and these alterations differ according to the trimester of gestation. Further research is needed to establish the cut-off values for this category. Pregnant women can have better outcomes through physical activity.

Effect of sildenafil on maternal hemodynamics in pregnancies complicated by severe early-onset fetal growth restriction: planned subgroup analysis from a multicenter randomized placebo-controlled double-blind trial

OBJECTIVES

Fetal growth restriction (FGR) is associated with maternal cardiovascular changes. Sildenafil, a phosphodiesterase type-5 inhibitor, potentiates the actions of nitric oxide, and it has been suggested that it alters maternal hemodynamics, potentially improving placental perfusion. Recently, the Dutch STRIDER trial was stopped prematurely owing to excess neonatal mortality secondary to pulmonary hypertension. The main aim of this study was to investigate the effect of sildenafil on maternal hemodynamics in pregnancies with severe early-onset FGR.

METHODS

This was a cardiovascular substudy within a UK multicenter, placebo-controlled trial, in which 135 women with a singleton pregnancy and severe early-onset FGR (defined as a combination of estimated fetal weight or abdominal circumference below the 10^th centile and absent/reversed end-diastolic flow in the umbilical artery on Doppler velocimetry, diagnosed between 22 + 0 and 29 + 6 weeks' gestation) were assigned randomly to receive either 25 mg sildenafil three times daily or placebo until 32 + 0 weeks' gestation or delivery. Maternal blood pressure (BP), heart rate (HR), augmentation index, pulse wave velocity (PWV), cardiac output, stroke volume (SV) and total peripheral resistance were recorded before randomization, 1-2 h and 48-72 h post-randomization, and 24-48 h postnatally. For continuous data, analysis was performed using repeated measures ANOVA methods including terms for timepoint, treatment allocation and their interaction.

RESULTS

Included were 134 women assigned randomly to sildenafil (n = 69) or placebo (n = 65) who had maternal BP and HR recorded at baseline. At 1-2 h post-randomization, compared with baseline values, sildenafil increased maternal HR by 4 bpm more than did placebo (mean difference, 5.00 bpm (95% CI, 1.00-12.00 bpm) vs 1.25 bpm (95% CI, -5.38 to 7.88 bpm); P = 0.004) and reduced systolic BP by 1 mmHg more (mean difference, -4.13 mmHg (95% CI, -9.94 to 1.44 mmHg) vs -2.75 mmHg (95% CI, -7.50 to 5.25 mmHg); P = 0.048). Even after adjusting for maternal mean arterial pressure, sildenafil reduced aortic PWV by 0.60 m/s more than did placebo (mean difference, -0.90 m/s (95% CI, -1.31 to -0.51 m/s) vs -0.26 m/s (95% CI, -0.75 to 0.59 m/s); P = 0.001). Sildenafil was associated with a non-significantly greater decrease in SV index after 1-2 h post-randomization than was placebo (mean difference, -5.50 mL/m² (95% CI, -11.00 to -0.50 mL/m² ) vs 0.00 mL/m² (95% CI, -5.00 to 4.00 mL/m² ); P = 0.056).

CONCLUSIONS

Sildenafil in a dose of 25 mg three times daily increases HR, reduces BP and reduces arterial stiffness in pregnancies complicated by severe early-onset FGR. These changes are short term, modest and consistent with the anticipated vasodilatory effect. They have no short- or long-term clinical impact on the mother. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Central haemodynamics in normal pregnancy: a prospective longitudinal study

OBJECTIVE

To conduct a longitudinal evaluation of the central haemodynamic adaptations of normal pregnancy.

METHODS

This was a prospective longitudinal study involving healthy, normotensive women who were having an uncomplicated, singleton pregnancy. Brachial and central SBP, DBP, mean arterial pressure (MAP), brachial and central pulse pressure (PP), aorta-to-brachial pulse pressure amplification (AMPA-B), heart rate (HR), augmentation index adjusted for HR (AIx75), carotid-femoral pulse wave velocity (cfPWV) and cardiac output (CO) were measured at a mean gestational age of 14, 24 and 36 weeks.

RESULTS

One hundred women were followed prospectively throughout pregnancy. Brachial and central SBP, DBP and MAP decreased slightly in early gestation, followed by a significant increase in late gestation (P < 0.05). Brachial PP was lowest in the final trimester (P = 0.011) whereas central PP remained unchanged, resulting in a significant decrease in AMPA-B (P < 0.001). HR and AIx75 rose continuously throughout pregnancy (P < 0.001). A significant fall in cfPWV was observed mid-pregnancy, which remained significant after adjustment for MAP and HR (P < 0.05). CO rose mid-pregnancy, before returning to baseline values by week 36 of gestation (P < 0.05).

CONCLUSION

To our knowledge, this is the largest prospective study to evaluate several central haemodynamic parameters in normotensive pregnancies, including adjusted-AIx and the gold-standard cfPWV. These data are a necessary foundation for the establishment of pregnancy-specific reference values and provide reference data for future trial design.

Preeclampsia: Maternal Systemic Vascular Disorder Caused by Generalized Endothelial Dysfunction Due to Placental Antiangiogenic Factors

Preeclampsia, a systemic vascular disorder characterized by new-onset hypertension and proteinuria after 20 weeks of gestation, is the leading cause of maternal and perinatal morbidity and mortality. Maternal endothelial dysfunction caused by placental factors has long been accepted with respect to the pathophysiology of preeclampsia. Over the past decade, increased production of placental antiangiogenic factors has been identified as a placental factor leading to maternal endothelial dysfunction and systemic vascular dysfunction. This review summarizes the recent advances in understanding the molecular mechanisms of endothelial dysfunction caused by placental antiangiogenic factors, and the novel clinical strategies based on these discoveries.

Vascular Function and Serum Lipids in Women with Spontaneous Preterm Delivery and Term Controls

Background: Spontaneous preterm delivery (sPTD) is associated with a twofold increased risk of future maternal cardiovascular disease. We hypothesized that women with sPTD would demonstrate greater vascular dysfunction postpartum compared to women with term delivery. Materials and Methods: In a case-controlled, matched pilot study, we enrolled 20 women with sPTD (gestation ≤34 weeks), and 20 term control women (gestation ≥39 weeks) were matched for age (±5 years), parity, ethnicity, and route of delivery. Vascular function, serum lipids, C-reactive protein, and interleukin-6 were completed within 24-72 hours postpartum. Statistical analysis included paired t-tests based on match and mixed effects linear regression models and adjusted for potential confounders. Results: The mean age for sPTD and term controls was 33 ± 6 years and 32 ± 6 years, respectively. Women with sPTD had significantly lower augmentation index-75 (24.1% ± 16.1% vs. 39.9% ± 15.2%, p = 0.001) and central pulse pressure (29.1 ± 5.4 mmHg vs. 34.6 ± 4.7 mmHg, p = 0.004), but no difference in pulse wave velocity (5.1 ± 1.6 m/s vs. 5.6 ± 1.5 m/s, p = 0.12) compared to controls. Women with sPTD had significantly lower high-density lipoprotein cholesterol (59.4 ± 12.5 mg/dL vs. 67.6 ± 13.1 mg/dL, p = 0.035) compared to controls. Analysis of chorioamnionitis and magnesium sulfate did not alter the results. Conclusions: Women with sPTD have signs of lower smooth muscle tone in the early postpartum period compared to women with term delivery. Further research is required to understand mechanistic pathways in sPTD and future maternal cardiovascular disease risk.

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.

Longitudinal changes in vascular function parameters in pregnant women with chronic hypertension and association with adverse outcome: a cohort study

OBJECTIVES

Raised vascular function measures are associated with adverse maternal and perinatal outcomes in low-risk pregnancy. This study aimed to evaluate the association between longitudinal vascular function parameters and adverse outcome in pregnant women with chronic hypertension, and to assess whether these measures vary according to baseline parameters such as black ethnicity.

METHODS

This was a nested cohort study of women with chronic hypertension and a singleton pregnancy recruited to the PANDA (Pregnancy And chronic hypertension: NifeDipine vs lAbetalol as antihypertensive treatment) study at one of three UK maternity units. Women had serial pulse-wave analyses performed using the Arteriograph®, while in a sitting position, from 12 weeks' gestation onwards. Statistical analysis was performed using random-effects logistic regression models. Longitudinal vascular parameters were compared between women who developed superimposed pre-eclampsia (SPE) and those who did not, between women who delivered a small-for-gestational-age (SGA) infant (birth weight < 10^th centile) and those who delivered an infant with birth weight ≥ 10^th centile and between women of black ethnicity and those of non-black ethnicity.

RESULTS

The cohort included 97 women with chronic hypertension and a singleton pregnancy, of whom 90% (n = 87) were randomized to antihypertensive treatment and 57% (n = 55) were of black ethnicity, with up to six (mean, three) longitudinal vascular function assessments. SPE was diagnosed in 18% (n = 17) of women and 30% (n = 29) of infants were SGA. In women who developed subsequent SPE, compared with those who did not, mean brachial systolic blood pressure (SBP) (148 mmHg vs 139 mmHg; P = 0.002), mean diastolic blood pressure (DBP) (87 mmHg vs 82 mmHg; P = 0.01), mean central aortic pressure (139 mmHg vs 128 mmHg; P = 0.001) and mean augmentation index (AIx-75) (29% vs 22%; P = 0.01) were significantly higher across gestation. In women who delivered a SGA infant compared to those who delivered an infant with birth weight ≥ 10^th centile, mean brachial SBP (146 mmHg vs 138 mmHg; P = 0.001), mean DBP (86 mmHg vs 82 mmHg; P = 0.01), mean central aortic pressure (137 mmHg vs 127 mmHg; P < 0.0001) and mean pulse-wave velocity (9.1 m/s vs 8.5 m/s; P = 0.02) were higher across gestation. No longitudinal differences were found in vascular function parameters in women of black ethnicity compared with those of non-black ethnicity.

CONCLUSION

There were persistent differences in vascular function parameters and brachial blood pressure throughout pregnancy in women with chronic hypertension who later developed adverse maternal or perinatal outcome. Further investigation into the possible clinical use of these findings is warranted. 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.

Biology of preeclampsia: Combined actions of angiogenic factors, their receptors and placental proteins

Although massive efforts have been undertaken to elucidate the etiology of the pregnancy syndrome preeclampsia, its developmental origin remains a mystery. Most efforts of the last decade have focused on biomarkers to predict and/or diagnose preeclampsia, including the anti-angiogenic factor sFlt-1 (soluble fms-like tyrosin kinase-1), the angiogenic factor PGF (placental growth factor) and PP13 (placental protein 13). The origins of these marker proteins are still under debate, and so far their actions have only been describe separate from each other. This study will focus on the origins and actions of all three markers during pregnancy and outside pregnancy and will describe a scenario where all three markers act synergistically to rescue the mother from the deleterious effects of the debris that is released from the placenta during preeclampsia. This more holistic approach may open new avenues to think about maternal-fetal interactions and putative therapies.

Changes of Arterial Pulse Waveform Characteristics with Gestational Age during Normal Pregnancy

Arterial pulse waveform analysis has been widely used to reflect physiological changes in the cardiovascular system. This study aimed to comprehensively investigate the changes of waveform characteristics of both photoplethysmographic (PPG) and radial pulses with gestational age during normal pregnancy. PPG and radial pulses were simultaneously recorded from 130 healthy pregnant women at seven gestational time points. After normalizing the arterial pulse waveforms, the abscissa of notch point, the total pulse area and the reflection index were extracted and compared between different measurement points and between the PPG and radial pulses using post-hoc multiple comparisons with Bonferrioni correction. The results showed that the effect of gestational age on all the three waveform characteristics was significant (all p < 0.001) after adjusting for maternal age, heart rate and blood pressures. All the three waveform characteristics demonstrated similar changing trends with gestational age, and they were all significantly different between the measurements from gestational week 12–15 and the others (all p < 0.05, except for the PPG total pulse area between the first and second measurement points). In conclusion, this study has comprehensively quantified similar changes of both PPG and radial pulse waveform characteristics with gestational age.

Haemodynamic differences amongst women who were screened for gestational diabetes in comparison to healthy controls

AIM

To assess the changes in haemodynamics amongst pregnant women who were screened for gestational diabetes mellitus (GDM) in comparison to low-risk healthy pregnant controls.

METHODOLOGY

A total of 120 pregnant women of mean (standard deviation) age 31.03 (5.41) years who attended their oral glucose tolerance test as part of the national screening for GDM (study), and 60 low-risk healthy pregnant women (control) of mean age 29.71 (5.33) years, were invited to participate in this study. All women included in the study booked at the University Hospitals of Leicester NHS Trust and fulfilled the relevant inclusion criteria. Non-invasive assessment of arterial stiffness and cardiac output were undertaken on participants between 26 and 28 weeks of pregnancy. The mean difference between GDM and low-risk group for each of the arterial stiffness and cardiac output measurements was assessed by a two-sample unpaired t-test.

RESULTS

Significant differences were found between the study and control groups for brachial (-64.5 vs. -69.5, p < 0.04) and aortic augmentation indices (5.2 vs. 2.7, p = 0.04), though there was no significant difference for PWV (8.3 vs. 8.1, p = 0.49). Cardiac output (7.6 vs. 7.0, p = 0.011), stroke volume (84.4 vs. 76.9, p = 0.013) and central mean arterial pressure (71 vs. 58, <0.001) were also significantly different between groups. However, no significant differences were reported for heart rate, systolic and diastolic blood pressure, or total peripheral resistance.

CONCLUSION

Pregnant women at risk of GDM between gestational weeks 26 and 28 had significantly increased measures of arterial stiffness, as assessed by brachial and aortic augmentation indices, compared with low-risk healthy controls. Whether these women are at greater long-term cardiovascular disease risk warrants further investigation.

Association Between Prepregnancy Cardiovascular Function and Subsequent Preeclampsia or Fetal Growth Restriction

Preeclampsia and fetal growth restriction during pregnancy are associated with increased risk of maternal cardiovascular disease later in life. It is unclear whether this association is causal or driven by similar antecedent risk factors. Clarification requires recruitment before conception which is methodologically difficult with high attrition rates and loss of outcome numbers to nonconception/miscarriage. Few prospective studies have, therefore, been adequately powered to address these questions. We recruited 530 healthy women (mean age: 35.0 years) intending to conceive and assessed cardiac output, cardiac index, stroke volume, total peripheral resistance, mean arterial pressure, and heart rate before pregnancy. Participants were followed to completion of subsequent pregnancy with repeat longitudinal assessments. Of 356 spontaneously conceived pregnancies, 15 (4.2%) were affected by preeclampsia and fetal growth restriction. Women who subsequently developed preeclampsia/fetal growth restriction had lower preconception cardiac output (4.9 versus 5.8 L/min; P=0.002) and cardiac index (2.9 versus 3.3 L/min per meter²; P=0.031) while mean arterial pressure (87.1 versus 82.3 mm Hg; P=0.05) and total peripheral resistance (1396.4 versus 1156.1 dynes sec cm^-5; P<0.001) were higher. Longitudinal trajectories for cardiac output and total peripheral resistance were similar between affected and healthy pregnancies, but the former group showed a more exaggerated fall in mean arterial pressure in the first trimester, followed by a steeper rise and a steeper fall to postpartum values. Significant relationships were observed between cardiac output, total peripheral resistance, and mean arterial pressure and gestational epoch. We conclude that in healthy women, an altered prepregnancy hemodynamic phenotype is associated with the subsequent development of preeclampsia/fetal growth restriction.

The effects of metformin on maternal haemodynamics in gestational diabetes mellitus: A pilot study

BACKGROUND

Gestational diabetes mellitus (GDM) is a major clinical challenge and is likely to remain so as the incidence of GDM continues to increase.

AIM

To assess longitudinal changes in maternal haemodynamics amongst women diagnosed with GDM requiring either metformin or dietary intervention in comparison to low-risk healthy controls.

METHODOLOGY

Fifty-six pregnant women attending their first appointment at the GDM clinic and 60 low-risk healthy pregnant controls attending their routine antenatal clinics were recruited and assigned to three groups: GDM Metformin (GDM-M), GDM Diet (GDM-D) and Control. Non-invasive assessment of maternal haemodynamics, using recognised measures of arterial stiffness and central blood pressure (Arteriograph®), were undertaken under controlled conditions within four gestational windows: antenatal; AN1 (26-28 weeks), AN2 (32-34 weeks) and AN3 (37-40 weeks), and postnatal (PN) (6-8 weeks after delivery). Data were analysed using a linear mixed model incorporating gestational age and other relevant predictors, including age, blood pressure (BP), baseline bodyweight and pulse as fixed effects, and patient as a random effect.

RESULTS

Fitted linear mixed models showed evidence of a two-way interaction effect between groups (GDM-D, GDM-M and Control) and stages of gestation (AN1, AN2, AN3 and PN) for maternal haemodynamic parameters: brachial artery augmentation index (AIx) (p = 0.004), aortic AIx (p = 0.008), and central systolic BP (p = 0.001). However, differences in respect of aortic pulse wave velocity (p = 0.001) and heart rate (p < 0.001) were only significant for gestational stage. At AN2, we did not observe any evidence that the mean brachial Aix in the GDM-M was different from the control group (p = 0.158).

CONCLUSION

AIx and central systolic BP measures of arterial stiffness are adversely affected by GDM in comparison to controls during pregnancy. The possible beneficial effects of metformin therapy seen at 32 to 34 weeks of gestation require further exploration.

Association of Spontaneous Preterm Delivery and Future Maternal Cardiovascular Disease

Cardiovascular disease (CVD) risk factors are well established. However, little is known about a woman's cardiovascular response to pregnancy, which appears to be an early marker of future maternal CVD risk. Spontaneous preterm delivery (sPTD) has been associated with a ≤3-fold increased risk of maternal CVD death later in life compared with having a term delivery. This review focuses on 3 key areas to critically assess the association of sPTD and future maternal CVD risk: (1) CVD risk factors, (2) inflammatory biomarkers of interest, and (3) specific forms of vascular dysfunction, such as endothelial function and arterial stiffness, and mechanisms by which each may be linked to sPTD. The association of sPTD with subsequent future maternal CVD risk suggests that a woman's abnormal response to pregnancy may serve as her first physiological stress test. These findings suggest that future research is needed to understand why women with sPTD may be at risk for CVD to implement effective interventions earlier in a woman's life.

Longitudinal study to assess changes in arterial stiffness and cardiac output parameters among low-risk pregnant women

AIM

A single-centre, prospective longitudinal study to assess changes in maternal arterial stiffness and cardiac output parameters among low-risk healthy pregnant women.

METHODOLOGY

Thirty low-risk, healthy, pregnant women attending their routine antenatal dating ultrasound scan were recruited. Non-invasive assessment of arterial stiffness and cardiac output was undertaken at five gestational windows from 11 to 40 weeks of pregnancy. Data were analysed using a linear mixed model incorporating time and other relevant predictors as fixed effects, and patient as a random effect.

RESULTS

Gestational age had a significant effect on all arterial stiffness parameters, including brachial augmentation index (AIx) (p = .001), aortic AIx (p = .002) and aortic pulse wave velocity (p = .002). The aortic AIx (%) reduced during pregnancy: the lowest mean (standard error, SE) was 4.07 (1.01) at 28 weeks before it increased to 7.04 (SE 1.64) at 40 weeks. Similarly, non-invasive assessments of cardiac output (p < .001), stroke volume (p = .014), heart rate (p < .001) and total peripheral resistance (p < .001) demonstrated significant changes with gestational age. Mean cardiac output (l/m) increased during pregnancy reaching a peak at 28 weeks gestation 6.66 (SE 0.28), but dropped thereafter to reach 5.71 (SE 0.25) around term.

CONCLUSION

The current study provides pregnancy normograms for gestational changes in arterial stiffness and cardiac output parameters among low-risk, healthy pregnant women. Further work will be required to assess the risk of placental mediated diseases and pregnancy outcome among pregnant women with parameters outside the normal range.

Assessment of arterial function in pregnancy: recommendations of the International Working Group on Maternal Hemodynamics

There is strong evidence supporting the role of maternal arterial dysfunction in pregnancy-specific disorders such as pre-eclampsia and intrauterine growth restriction. As more work is focused towards this field, it is important that methods and interpretation of arterial function assessment are applied appropriately. Here, we summarize techniques and devices commonly used in maternal health studies, with consideration of their technical application in pregnant cohorts. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Pre-eclampsia: the Potential of GSNO Reductase Inhibitors

PURPOSE OF REVIEW

Pre-eclampsia remains a leading worldwide cause of maternal death and of perinatal morbidity. There remains no definitive treatment except delivery of the fetus.

RECENT FINDINGS

Recent insights into the cardiovascular changes that are evident prior to, during, and persist after pre-eclampsia have improved understanding of the underlying pathophysiology-disruption of normal endothelial function and decreased nitric oxide bioavailability. S-nitrosoglutathione (GSNO) is an endogenous S-nitrosothiol that acts as a NO pool and, by replenishing or preventing the breakdown of GSNO, endothelial dysfunction can be ameliorated. GSNO reductase inhibitors are a novel class of drug that can increase NO bioavailability. GSNO reductase inhibitors have demonstrated improvement of endothelial dysfunction in animal models, and in vivo human studies have shown them to be well tolerated. GSNOR inhibitors offer a potentially promising option for the management of pre-eclampsia.

Pathophysiology of preeclampsia: an angiogenic imbalance and long-lasting systemic vascular dysfunction

Preeclampsia is a systemic vascular disorder characterized by new-onset hypertension and proteinuria after 20 weeks of gestation. This condition targets several organs, including the kidneys, liver and brain, and is the leading cause of maternal and perinatal morbidity and mortality. Furthermore, recent evidence has revealed preeclampsia as a significant risk factor for future cardiovascular diseases in these women. Over the past decade, increasing evidence has indicated that maternal angiogenic imbalances caused by placental antiangiogenic factors play a central role in the systemic vascular dysfunction underling preeclampsia. The severity of the maternal antiangiogenic state correlates closely with maternal and perinatal outcomes. Assessing angiogenic imbalance and several vascular function tests have also emerged as a way of detecting systemic vascular dysfunction during pregnancy. This review summarizes the current understanding of the pathophysiology of preeclampsia, its clinical applications and clinical evidence for future cardiovascular risks.

Association between uterine artery Doppler blood flow changes and arterial wall elasticity in pregnant women

INTRODUCTION

Uterine artery (UtA) Doppler velocimetry changes and increased arterial stiffness are associated with preeclampsia. We aimed to investigate the relation between UtA velocimetry changes and arterial stiffness in pregnant women.

METHODS

Doppler velocimetry and photoplethysmographic digital pulse wave analysis (DPA) were performed in 173 pregnant women in the second or the third trimester, where UtA Doppler pulsatility index (PI), diastolic notching, and UtA score (UAS) combining notching and high PI were calculated. DPA stiffness parameters representing large arteries were ejection elasticity index (EEI) and b/a, small arteries dicrotic index (DI) and d/a, and global stiffness the aging index (AI).

RESULTS

One hundred and thirty women had normal Doppler and 43 had diastolic notching, of whom nine had high PI. DI indicated increased stiffness in small arteries when notching was present (p = 0.044) and showed a significant but weak correlation to UAS (p = 0.025, tau 0.12). EEI and b/a indicated increased large artery stiffness (p ≤0.014), d/a small artery stiffness (p = 0.023), and AI a systemic stiffness (p = 0.040) when high PI.

CONCLUSION

High UtA PI was associated with increased systemic arterial stiffness, whereas notching was related to increased stiffness in small arteries only. This indicates pathophysiological differences between the two Doppler parameters.

Why non-invasive maternal hemodynamics assessment is clinically relevant in early pregnancy: a literature review

Background

The maternal cardiovascular system adapts quickly when embryo implantation is recognized by the body. Those adaptations play an important role, as a normal cardiovascular adaptation is a requirement for a normal course of pregnancy. Disturbed adaptations predispose to potential hypertensive disorders further in pregnancy [1–3]. This report aims to briefly inform the obstetricians, general practitioners and midwives, who are the key players in detecting and treating hypertensive disorders during pregnancy.

Methods

The PubMed database was used as main tool to find studies involving clearly defined first trimester hemodynamic changes in normal pregnancies and hypertensive pregnancies. In addition, the bibliographies of these studies were investigated for further relevant literature.

Results

A comprehensive overview is given concerning the normal adaptations in the cardiovascular tree in a first trimester pregnancy. Additionally, signs of abnormal cardiovascular changes observed in first trimester are described together with the normal reference range for each non-invasive, easily applicable technique for maternal hemodynamics assessment.

Conclusions

With a combination of techniques, it is possible to integrate and evaluate the maternal heart, veins and arteries at 12 weeks of pregnancy. Applying those techniques into the daily clinic opens perspectives to prevention and prophylactic treatment, aiming for a reduction of the risk for hypertension during pregnancy.

Endothelial dysfunction and arterial stiffness in pre-eclampsia demonstrated by the EndoPAT method

OBJECTIVES

The EndoPAT method has been used as a non-invasive method for assessing endothelial function in several non-pregnant populations. We investigated its possible use in assessing endothelial dysfunction in pre-eclampsia.

METHODS

Two hundred and fifteen participants were recruited and grouped as pre-eclamptic cases (105) and normotensive controls (110). Endothelial function and arterial stiffness were measured as reactive hyperaemia index and augmentation index, respectively, using the EndoPAT 2000 machine.

RESULTS

The reactive hyperaemia index was significantly lower in the pre-eclamptic group compared to the normotensive group (p < 0.05). Augmentation index on the other hand was significantly higher in the pre-eclamptic group compared to the normotensive group (p < 0.0001).

CONCLUSION

The EndoPAT method demonstrates endothelial dysfunction and arterial stiffness in pre-eclampsia.

Changes in Central Hemodynamics in Women With Hypertensive Pregnancy Between Before and After Delivery

The authors tested the hypothesis that central hemodynamic parameters in women with hypertensive disorders of pregnancy (HDP) change between before and after delivery. A total of 137 pregnant women were studied: 72 with HDP, 42 with chronic hypertension (CH), and 23 with white-coat hypertension (WCH; control group). Aortic augmentation index adjusted by heart rate 75 beats per minute (AIx@75), central pulse pressure (PP), total peripheral resistance (TPR), and cardiac output (CO) before and after delivery were recorded. AIx@75 and central PP were higher in the HDP group than in the control group, but both parameters declined after delivery until they were similar to the controls. AIx@75 and central PP, but not TPR or CO, were significantly decreased after delivery in the HDP group, but no such effects were seen in the other groups. These findings suggest that increased wave reflection caused by the stiffened aorta could be a key factor in the pathophysiology of HDP.

Preeclampsia and Vascular Function: A Window to Future Cardiovascular Disease Risk

Preeclampsia affects ∼3%-7% of all pregnancies and is the third leading cause of maternal mortality globally. Growing evidence indicates that preeclampsia results from vascular dysfunction, which also increases the risk for future cardiovascular events. Until recently, preeclampsia was considered a disorder limited to pregnancy, which fully resolved with the delivery of the placenta; however, it is now clear that women with a history of preeclampsia have approximately double the risk of future cardiovascular events compared to women with normotensive pregnancies. The aims of this review were to describe the hemodynamic and vascular changes that occur in normal and preeclamptic pregnancies, to review noninvasive methods to test vascular function, and to discuss the associated increased cardiovascular disease risk related to preeclampsia.

Prognostic models in obstetrics: available, but far from applicable

Health care provision is increasingly focused on the prediction of patients' individual risk for developing a particular health outcome in planning further tests and treatments. There has been a steady increase in the development and publication of prognostic models for various maternal and fetal outcomes in obstetrics. We undertook a systematic review to give an overview of the current status of available prognostic models in obstetrics in the context of their potential advantages and the process of developing and validating models. Important aspects to consider when assessing a prognostic model are discussed and recommendations on how to proceed on this within the obstetric domain are given. We searched MEDLINE (up to July 2012) for articles developing prognostic models in obstetrics. We identified 177 papers that reported the development of 263 prognostic models for 40 different outcomes. The most frequently predicted outcomes were preeclampsia (n = 69), preterm delivery (n = 63), mode of delivery (n = 22), gestational hypertension (n = 11), and small-for-gestational-age infants (n = 10). The performance of newer models was generally not better than that of older models predicting the same outcome. The most important measures of predictive accuracy (ie, a model's discrimination and calibration) were often (82.9%, 218/263) not both assessed. Very few developed models were validated in data other than the development data (8.7%, 23/263). Only two-thirds of the papers (62.4%, 164/263) presented the model such that validation in other populations was possible, and the clinical applicability was discussed in only 11.0% (29/263). The impact of developed models on clinical practice was unknown. We identified a large number of prognostic models in obstetrics, but there is relatively little evidence about their performance, impact, and usefulness in clinical practice so that at this point, clinical implementation cannot be recommended. New efforts should be directed toward evaluating the performance and impact of the existing models.

Pregnancy induces persistent changes in vascular compliance in primiparous women

OBJECTIVE

Pregnancy induces rapid, progressive, and substantial changes to the cardiovascular system. The low recurrence risk of preeclampsia, despite familial predisposition, suggests an adaptation associated with pregnancy that attenuates the risk for subsequent preeclampsia. We aimed to evaluate the persistent effect of pregnancy on maternal cardiovascular physiology.

STUDY DESIGN

Forty-five healthy nulliparous women underwent baseline cardiovascular assessment before conception and repeated an average of 30 months later. After baseline evaluation, 17 women conceived singleton pregnancies and all delivered at term. The remaining 28 women comprised the nonpregnant control group. We measured mean arterial blood pressure, cardiac output, plasma volume, pulse wave velocity, uterine blood flow, and flow-mediated vasodilation at each visit.

RESULTS

There was a significant decrease in mean arterial pressure from the prepregnancy visit to postpartum in women with an interval pregnancy (prepregnancy, 85.3±1.8; postpartum, 80.5±1.8 mm Hg), with no change in nonpregnant control subjects (visit 1, 80.3±1.4; visit 2, 82.8±1.4 mm Hg) (P=.002). Pulse wave velocity was significantly decreased in women with an interval pregnancy (prepregnancy, 2.73±0.05; postpartum, 2.49±0.05 m/s), as compared with those without an interval pregnancy (visit 1, 2.56±0.04; visit 2, 2.50±0.04 m/s) (P=.005). We did not observe a residual effect of pregnancy on cardiac output, plasma volume, uterine blood flow, or flow-mediated vasodilation.

CONCLUSION

Our observations of decreased mean arterial pressure and reduced arterial stiffness following pregnancy suggest a significant favorable effect of pregnancy on maternal cardiovascular remodeling. These findings may represent a mechanism by which preeclampsia risk is reduced in subsequent pregnancies.

Longitudinal changes in maternal corin and mid-regional proatrial natriuretic peptide in women at risk of pre-eclampsia

OBJECTIVE

Corin, an atrial natriuretic peptide-converting enzyme, has been found to promote trophoblast invasion and spiral artery remodeling. Yet, elevated maternal plasma atrial natriuretic peptide (ANP) and corin levels have been reported in pregnancies complicated by pre-eclampsia (PE). The aim of this study was to investigate longitudinal changes in maternal plasma levels of corin and mid-regional proatrial natriuretic peptide (MR-PANP) in pregnancies that develop PE and gestational hypertension (GH).

METHODS

This was a nested case-control study drawn from a larger prospective longitudinal study in singleton pregnancies identified as being at high risk for PE by screening at 11 + 0 to 13 + 6 weeks' gestation. Blood samples were taken every 4 weeks until delivery. Values were compared in pregnancies that developed preterm PE (requiring delivery before 37 weeks' gestation), term PE, GH and those that remained normotensive.

RESULTS

A total of 471 samples were analyzed from 122 women, including 85 that remained normotensive, 12 that developed GH, 13 term PE and 12 preterm PE. In the normotensive group, log10 corin levels were associated with gestational age (P < 0.01), whereas log10 MR-PANP levels were not. In the preterm-PE group, compared with the normotensive group, corin was significantly lower until 20 weeks' gestation (P = 0.001). In the GH and term-PE groups, corin did not differ significantly from the normotensive group (P = 0.637 and P = 0.161, respectively). Compared with the normotensive group, MR-PANP levels were significantly higher in the pregnancies that developed preterm PE and GH (P = 0.046 and P = 0.019, respectively), but not term PE (P = 0.467).

CONCLUSION

Maternal-plasma corin and MR-PANP could potentially be useful biomarkers for the prediction of preterm PE.

Longitudinal changes in maternal hemodynamics in a population at risk for pre-eclampsia

OBJECTIVE

To investigate longitudinal changes in maternal hemodynamics from the first trimester onward in women who develop pre-eclampsia (PE) or gestational hypertension (GH).

METHODS

This was a prospective longitudinal study of singleton pregnancies identified by screening at 11 + 0 to 13 + 6 weeks' gestation as being at high risk for PE. Measurements of augmentation index (AIx), pulsed wave velocity (PWV) and aortic systolic blood pressure (SBPao) were taken every 4 weeks until delivery. Values were compared between women who developed preterm PE requiring delivery before 37 weeks, term PE or GH, and those who remained normotensive.

RESULTS

A total of 1198 observations were recorded in 245 women, including 181 who were normotensive, 22 with preterm PE, 22 with term PE and 20 with GH. In the normotensive group, there was a U-shaped relationship between AIx and gestational age with a trough at 25 weeks' gestation, whereas changes in levels of PWV or SBPao were minimal, with a mild increase from 25 and 30 weeks' gestation onward, respectively. In the GH and preterm PE groups, compared to the normotensive group, SBPao was higher and the difference did not change significantly with gestational age. In the term PE group, SBPao did not differ significantly from that in the normotensive group. In the preterm PE group compared to the normotensive group, PWV and AIx were significantly higher from 16-17 weeks' gestation onward and the difference increased with gestational age in both cases. In the term PE and GH groups, PWV and AIx did not differ significantly from normal.

CONCLUSION

This study describes temporal changes in AIx, PWV and SBPao in normotensive pregnant women and in women who develop PE or GH.

Abnormal pressure-wave reflection in pregnant women with chronic hypertension: association with maternal and fetal outcomes

The current study tested the hypothesis that abnormal pressure-wave reflection may have an important role in identifying pregnant women with chronic hypertension who might develop pre-eclampsia (PE) and/or fetal growth restriction. Pulse-wave analyses were performed to assess maternal arterial stiffness during 26-32 weeks of gestation in 41 women with chronic hypertension. We measured the central systolic pressure (CSP) and augmentation index (AIx) noninvasively using pulse waveforms of the radial artery with an automated applanation tonometric system. In a multiple regression analysis that included AIx-75 (AIx at a heart rate of 75 beats per minute), brachial systolic pressure, maternal height, smoking status, gestational age at testing and the presence of antihypertensive treatment at testing as independent determinants, AIx-75 was the only significant determinant of birth weight, whereas the brachial systolic pressure was not. In pregnant women with chronic hypertension who subsequently developed both superimposed PE and fetal growth restriction, CSP, AIx, AIx-75, and the brachial systolic and pulse pressures were all significantly higher than those who did not develop superimposed PE nor small for gestational age. In contrast, AIx-75 was the only significantly elevated hemodynamic parameter in patients who developed fetal growth restriction but not superimposed PE. In addition, CSP was the only significantly elevated hemodynamic parameter in patients who developed superimposed PE but not fetal growth restriction. Abnormal pressure-wave reflection during 26-32 weeks of gestation showed a stronger correlation with birth weight than conventional brachial blood pressure. Our findings might provide new insight into the pathophysiology of fetal growth restriction as well as superimposed PE in pregnancies complicated with chronic hypertension.

First trimester screening can predict adverse pregnancy outcomes

There has been an increasing drive over the last two decades to push the detection of women at risk of adverse pregnancy outcomes into the first trimester. This has led to a plethora of techniques, risk assessments and biomarkers, both fascinating and bewildering in its breadth. Despite the vast amount of knowledge available, it is often difficult to determine what is practicable and valuable for clinical practice. This is especially true as earlier diagnosis does not necessarily equate to improved outcomes for mother and child. We suggest that, at least for preeclampsia, fetal growth restriction, spontaneous preterm birth and gestational diabetes, there are effective first trimester tests available to identify the women at risk of subsequently developing complications. Unfortunately, there are no currently reliable first trimester tests available for identifying women at risk of stillbirth. It is likely that this field will continue to develop over time, and we hope that new and better strategies will continue to emerge to target these clinically important pathologies.

Reference values of maternal ophthalmic artery doppler variables in the first trimester of normal pregnancy

BACKGROUND

The aim of this study was to establish normative data for ophthalmic artery Doppler variables in the first trimester of normal pregnancy.

METHODS

Maternal ophthalmic artery Doppler signals were recorded in 409 singleton pregnancies at 11-14 weeks' gestation, in mothers presenting consecutively for routine antenatal care. Pulsatility and resistance indices (PI, RI), peak systolic velocity (PSV), first peak diastolic velocity (PD1), and peak ratio (PR) were measured. Quartile regression was used to estimate reference ranges in the late first trimester of pregnancy.

RESULTS

Mean ± SD values for maternal ophthalmic artery Doppler parameters between 11 and 14 weeks' gestation were RI = 0.81 ± 0.12, PI = 2.06 ± 0.57, PSV = 36.41 ± 12.1, PD1 = 21.07 ± 7.62, and PR = 0.58 ± 0.11. All clinical and Doppler variables were normally distributed. PD1 values were higher in patients who smoked, and in those with diabetes or a history of pre-eclampsia. PR values were higher in patients with diabetes and chronic hypertension, and lower in the nulliparous; these values declined as gestation advanced from 11 to 14 weeks, whereas the other variables remained unchanged.

CONCLUSIONS

We provide reference values for maternal ophthalmic artery Doppler variables in the first trimester of normal pregnancy.