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

Reference-range of arterial stiffness by cardio-ankle vascular index in normal pregnancy

OBJECTIVE

To establish the arterial stiffness, represented by the cardio-ankle vascular index (CAVI) at various gestational ages among low-risk pregnant women. The second objective is to construct the reference range of mean arterial pressure and maternal heart rate during pregnancy.

METHODS

This cross-sectional study was conducted on low risk pregnant Thai women, meeting the following inclusion criteria: 1) singleton pregnant women aged 18 years old or over; 2) gestational age between 11 and 40 weeks; 3) low-risk pregnancy without any underlying medical diseases; and 4) known final pregnancy outcomes. Pregnancy-induced hypertension, gestational diabetes and fetal growth restriction were excluded. The mean CAVI, mean arterial pressure (MAP), and heart rate were measured at each gestational age.

RESULTS

A total of 329 measurements for each parameter were available for analysis. CAVI was significantly correlated with gestational age with the best fitted model: CAVI = 6.952 - 0.076(GA) + 0.001(GA)2; SD = 0.742 (R2 = 0.049; p-value < 0.001). The maternal age and pre-pregnancy BMI were correlated with CAVI. CAVI gradually increased with maternal age and decreased with increasing body mass index (BMI). The MAP and heart rate of normal pregnancy in each gestation were conducted.

CONCLUSION

The reference range of CAVI in normal pregnancies as a function of gestational age and the model for predicting CAVI based on multiple regression analysis are constructed and presented. These reference ranges may be useful in predicting risk of cardiovascular disorders during pregnancy.

Comparison of Central Aortic Pressure between Women with Preeclampsia and Normotensive Postpartum Women from an Urban Region of Western Mexico

Background and Objectives: Central aortic pressure (CAP) can be measured through noninvasive methods, and CAP wave analysis can provide information about arterial stiffness. The objective of this study was to compare CAP in women with preeclampsia and normotensive postpartum women from an urban region in western Mexico. Materials and Methods: We recruited 78 women in immediate puerperium, including 39 with preeclampsia and 39 with normotension, who received delivery care in our hospital between September 2017 and January 2018. Pulse wave analysis was used to assess central hemodynamics as well as arterial stiffness with an oscillometric device. For this purpose, the measurement of the wave of the left radial artery was obtained with a wrist applanation tonometer and the ascending aortic pressure wave was generated using the accompanying software (V 1.1, Omron, Japan). Additionally, the systolic CAP, diastolic pressure, pulse pressure, heart rate, and rise rate adjusted for a heart rate of 75 bpm were determined. The radial pulse wave was calibrated using the diastolic and mean arterial pressures obtained from the left brachial artery. For all the statistical analyses, we considered p < 0.05 to be significant. Results: The results were as follows: a systolic CAP of 125.40 (SD 15.46) vs. 112.10 (SD 10.12) with p < 0.0001 for women with and without preeclampsia, respectively. Systolic CAP was significantly elevated in women with preeclampsia and could indicate an elevated risk of cardiovascular disease. Conclusion: CAP is an important parameter that can be measured in this group of patients and is significantly elevated in women with postpartum preeclampsia, even when the brachial blood pressure is normal.

Diagnosing Arterial Stiffness in Pregnancy and Its Implications in the Cardio-Renal-Metabolic Chain

Cardio-renal and metabolic modifications during gestation are crucial determinants of foetal and maternal health in the short and long term. The cardio-renal metabolic syndrome is a vicious circle that starts in the presence of risk factors such as obesity, hypertension, diabetes, kidney disease and ageing, all predisposing to a status dominated by increased arterial stiffness and alteration of the vascular wall, which eventually damages the target organs, such as the heart and kidneys. The literature is scarce regarding cardio-renal metabolic syndrome in pregnancy cohorts. The present paper exposes the current state of the art and emphasises the most important findings of this entity, particularly in pregnant women. The early assessment of arterial function can lead to proper and individualised measures for women predisposed to hypertension, pre-eclampsia, eclampsia, and diabetes mellitus. This review focuses on available information regarding the assessment of arterial function during gestation, possible cut-off values, the possible predictive role for future events and modalities to reverse or control its dysfunction, a fact of crucial importance with excellent outcomes at meagre costs.

Hemodynamic pathways of gestational hypertension and preeclampsia

Gestational hypertension and preeclampsia are the 2 main types of hypertensive disorders in pregnancy. Noninvasive maternal cardiovascular function assessment, which helps obtain information from all the components of circulation, has shown that venous hemodynamic dysfunction is a feature of preeclampsia but not of gestational hypertension. Venous congestion is a known cause of organ dysfunction, but its potential role in the pathophysiology of preeclampsia is currently poorly investigated. Body water volume expansion occurs in both gestational hypertension and preeclampsia, and this is associated with the common feature of new-onset hypertension after 20 weeks of gestation. Blood pressure, by definition, is the product of intravascular volume load and vascular resistance (Ohm's law). Fundamentally, hypertension may present as a spectrum of cardiovascular states varying between 2 extremes: one with a predominance of raised cardiac output and the other with a predominance of increased total peripheral resistance. In clinical practice, however, this bipolar nature of hypertension is rarely considered, despite the important implications for screening, prevention, management, and monitoring of disease. This review summarizes the evidence of type-specific hemodynamic profiles in the latent and clinical stages of hypertensive disorders in pregnancy. Gestational volume expansion superimposed on an early gestational closed circulatory circuit in a pressure- or volume-overloaded condition predisposes a patient to the gradual deterioration of overall circulatory function, finally presenting as gestational hypertension or preeclampsia-the latter when venous dysfunction is involved. The eventual phenotype of hypertensive disorder is already predictable from early gestation onward, on the condition of including information from all the major components of circulation into the maternal cardiovascular assessment: the heart, central and peripheral arteries, conductive and capacitance veins, and body water content. The relevance of this approach, outlined in this review, openly invites for more in-depth research into the fundamental hemodynamics of gestational hypertensive disorders, not only from the perspective of the physiologist or the scientist, but also in assistance of clinicians toward understanding and managing effectively these severe complications of pregnancy.

Preeclampsia has two phenotypes which require different treatment strategies

The opinion on the mechanisms underlying the pathogenesis of preeclampsia still divides scientists and clinicians. This common complication of pregnancy has long been viewed as a disorder linked primarily to placental dysfunction, which is caused by abnormal trophoblast invasion, however, evidence from the previous two decades has triggered and supported a major shift in viewing preeclampsia as a condition that is caused by inherent maternal cardiovascular dysfunction, perhaps entirely independent of the placenta. In fact, abnormalities in the arterial and cardiac functions are evident from the early subclinical stages of preeclampsia and even before conception. Moving away from simply observing the peripheral blood pressure changes, studies on the central hemodynamics reveal two different mechanisms of cardiovascular dysfunction thought to be reflective of the early-onset and late-onset phenotypes of preeclampsia. More recent evidence identified that the underlying cardiovascular dysfunction in these phenotypes can be categorized according to the presence of coexisting fetal growth restriction instead of according to the gestational period at onset, the former being far more common at early gestational ages. The purpose of this review is to summarize the hemodynamic research observations for the two phenotypes of preeclampsia. We delineate the physiological hemodynamic changes that occur in normal pregnancy and those that are observed with the pathologic processes associated with preeclampsia. From this, we propose how the two phenotypes of preeclampsia could be managed to mitigate or redress the hemodynamic dysfunction, and we consider the implications for future research based on the current evidence. Maternal hemodynamic modifications throughout pregnancy can be recorded with simple-to-use, noninvasive devices in obstetrical settings, which require only basic training. This review includes a brief overview of the methodologies and techniques used to study hemodynamics and arterial function, specifically the noninvasive techniques that have been utilized in preeclampsia research.

Highlighting the Mechanistic Relationship Between Perinatal Depression and Preeclampsia: A Scoping Review

BACKGROUND

Although there is scientific literature supporting an association between depression and preeclampsia (PE), little is known about the underlying mechanistic pathways that may explain these observed associations. Thus, this study aimed to outline the relationship between depression and PE, and to highlight the underlying cardiovascular and metabolic risk factors that are common to both.

METHODS

A scoping review of the literature was conducted in Medline, Scopus, and Web of Science.

RESULTS

From 706 articles initially identified, 23 articles met the inclusion criteria and were included in this review. Although some studies reported a positive association between PE and postpartum depressive symptoms, challenges comparing different methodologies, measurement instruments and when measurements were administered, and patient populations do not permit a decisive conclusion. In addition, very few studies addressed potential underlying mechanisms that may be contributing to observed associations; thus, a secondary search was conducted to identify cardiovascular and metabolic risk factors that are common to both depression and PE.

CONCLUSION

The cardiovascular and metabolic risk factors (i.e., increased inflammation and oxidative stress and decreased vascular and endothelial function) common to both depression and PE suggest that these factors may contribute as underlying mechanisms in both conditions. These similarities underscore the importance to better understand these mechanisms so preventative and therapeutic strategies could be developed to improve maternal health.

Mildly elevated thyroid-stimulating hormone is associated with endothelial dysfunction and severe preeclampsia among pregnant women with insufficient iodine intake in Eastern Cape province, South Africa

BACKGROUND

Preeclampsia and hypothyroidism are associated with endothelial dysfunction. Iodine deficiency is a risk factor for subclinical hypothyroidism in pregnancy. However, there is a paucity of data on the relationship between iodine nutrition state in pregnancy, the degree of endothelial dysfunction, and the risk of preeclampsia.

METHODS

Ninety-five normotensive pregnant women, 50 women with preeclampsia with no severe features, and 50 women with severe preeclampsia were enrolled into the current study from the maternity units of Nelson Mandela Academic Hospital and Mthatha Regional Hospitals in Eastern Cape Province, South Africa. Urinary iodine concentration (UIC), serum markers of thyroid function, aortic augmentation index, and pulse wave velocity (PWV) were compared.

RESULTS

Median UIC was 167.5, 127.7, and 88.5 µg/L, respectively for normotensive pregnant women, those with preeclampsia and severe preeclampsia (p = .150). Participants with severe preeclampsia had significantly higher median thyroid-stimulating hormone (TSH) and oxidized LDL than normotensive and preeclamptic women without severe features (respectively 3.0, 2.3, and 2.3 IU/L; 1.2, 1.0, and 1.0 IU/L, p < .05). The median Aortic augmentation index was 7.5, 19.0, and 21.0 (p < .001), and the pulse wave velocity 5.1, 5.7, and 6.3, respectively for normotensive, preeclampsia, and severe preeclampsia participants (both p < .001). In linear regressions, TSH, age, and hypertensive disease were independent predictors of elevated PWV.

CONCLUSION

Upper normal-range TSH levels in women with severe preeclampsia were associated with markers of endothelial dysfunction. The low UIC and trend towards the elevation of thyroglobulin suggest that inadequate iodine intake may have increased TSH levels and indirectly caused endothelial dysfunction.

Smoking for two- effects of tobacco consumption on placenta

Tobacco smoking is an important public health issue recognized by the world health organization as one of the most serious, preventable risk factors for developing a series of pregnancy pathologies. Maternal smoking is positively associated with intrauterine growth restriction (IUGR) and gestational diabetes (GDM), but negatively associated with preeclampsia (PE). In this review, we examine epidemiological, clinical and laboratory studies of smoking effects on immunoregulation during pregnancy, trophoblast function, and placental vasculature development and metabolism. We aim to identify effects of tobacco smoke components on specific placental compartments or cells, which may contribute to the understanding of the influences of maternal smoking on placenta function in normal and pathological pregnancies. Data corroborates that in any trimester, smoking is unsafe for pregnancy and that its detrimental effects outweigh questionable benefits. The effects of maternal smoking on the maternal immune regulation throughout pregnancy and the impact of different tobacco products on fetal growth have not yet been fully understood. Smoking cessation rather than treatment with replacement therapies is recommended for future mothers because also single components of tobacco and its smoke may have detrimental effects on placental function.

Cardiovascular Risk Reduction in Women Following Hypertensive Disorders of Pregnancy - a Prospective, Randomised, Controlled Interventional Study

Background Women have a markedly increased lifetime risk for cardiovascular morbidity and mortality following hypertensive disorders of pregnancy. Arterial stiffness is regarded as a target parameter for reducing cardiovascular risk and can be modified by lifestyle changes.

Methods In a prospective, randomised, controlled interventional study, starting 6 weeks postpartum, the effect of nutritional intervention combined with an intensive 6-month cardiovascular exercise programme on arterial stiffness was investigated by means of pulse wave velocity (PWV) in 38 women with severe hypertensive disorder of pregnancy (preeclampsia with or without pre-existing hypertension and/or HELLP syndrome). A reference group was formed with postpartum women without pregnancy complications or known cardiovascular risk and the arterial stiffness was studied by means of PWV at the time of delivery. The PWV was measured in the intervention and control groups within a week after delivery and after 32 weeks (6 weeks + 6 months). A feasibility analysis was performed in addition.

Results 29 of 38 women with severe hypertensive disorder of pregnancy and 38 postpartum women in the reference group were included in the analysis (intervention group n = 14; control group n = 15; reference group n = 38). Adherence to a) the nutritional counselling and b) the intensive cardiovascular exercise programme was 73% and 79% respectively. A clinically significant difference (d = 0.65) in pulse wave velocity between the intervention and control groups was found after 6 months (6.36 ± 0.76 vs. 7.33 ± 2.25 m/s; group × time: p = 0.632). The PWV of the intervention group corresponded to that of the reference group at the end of the study (6.36 ± 0.76 m/s vs. 6.5 ± 0.70; d = 0.19), while the results in the control group differed markedly from this (7.33 ± 2.25 m/s; d = 0.56).

Conclusion The study documents the feasibility of lifestyle intervention with physical exercise after delivery (starting 6 weeks postpartum). The intervention showed a significant clinical effect by reducing arterial stiffness to the level of the reference group. Before this intervention can be included in the standard of care and prevention, follow-up studies must confirm these results and the medium-term effects on cardiovascular risk.

Arterial function in hypertensive pregnant women. Is arterial stiffness a marker for the outcomes in pregnancy?

AIMS

Hypertension (HTN) in pregnancy is a major cause of maternal, foetal and neonatal morbimortality in both developing and developed countries. Arterial stiffness is a predictor of cardiovascular events and can be assessed through augmentation index (AIx) and pulse wave velocity (PWV). This study was intended to analyse the arterial stiffness in three categories, hypertensive pregnant women vs. healthy women (both pregnant and non-pregnant).

MAIN METHODS

Between 2018 and 2019, 150 women were prospectively included into three homogenous groups, of equal sizes (N = 50): pregnant women with HTN (group 1), pregnant women without HTN (group 2), and non-pregnant women (group 3). We assessed pregnant women 3 times (in all three trimesters) and six weeks postpartum, and the women from the control group once.

KEY FINDINGS

Significant differences (p < 0.001) of the hemodynamic and arterial stiffness parameters and of the heart rate (HR) (p = 0.006) were observed between groups 1 and 2. Women with pregnancy-induced HTN had different values of arterial function parameters long time before the first signs of high blood pressure (BP) occurred. Also, body mass index (BMI) had a deleterious effect in all patients, but especially in pregnant HTN women. Significant differences (p < 0.001) between groups 2 and 3 were observed regarding the BP and aortic PWV (PWVao) and, as well, significant differences (p < 0.05) between BMI, aortic systolic BP (p = 0.02), brachial AIx (p = 0.01) and pulse pressure (PP) (p = 0.049) values.

SIGNIFICANCE

The current study emphasizes the importance of the assessment of arterial function parameters and BMI as markers for future BP values and outcomes throughout gestation.

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.

The relationship between maternal characteristics and carotid intima-media thickness using an automated ultrasound technique

Objective: To investigate CIMT and its relationship with maternal demographic characteristics in healthy pregnancy. Methods: CIMT was measured using an au. Results: CIMT showed no relationship with gestational age (rho=-0.124, p=0.335), parity (Z=-0.055, p=0.960) and MAP (rho=0.110, p=0.393). A relationship was found between CIMT and maternal age (rho=0.277, p=0.028), booking BMI (rho=0.278, p=0.027), and BMI at time of study (rho=0.287, p=0.023). CIMT ranged from 0.30-0.80mm, the 97.5th percentile was 0.63 mm. Conclusion: In healthy pregnancy, we reported CIMT was related to BMI and maternal age but not parity or gestational age.

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.

Pregnancy-related events associated with subclinical cardiovascular disease burden in late midlife: SWAN

BACKGROUND AND AIMS

Reproductive factors are associated with later life CVD in women (e.g., age at first birth, preeclampsia, gestational diabetes), but studies have focused largely on premenopausal women. We examined the relationship of reproductive factors with subclinical CVD burden in late midlife women.

METHODS

We included 964 parous women from the Study of Women's Health Across the Nation (SWAN), who completed a reproductive history questionnaire at the 13th SWAN visit (2011-2012), and a carotid ultrasound and brachial-ankle pulse wave velocity (baPWV) assessment. The primary outcomes were carotid intima-media thickness, plaque, and baPWV; our secondary outcome was a composite subclinical CVD index created using these measures. Linear and logistic regression was performed to examine associations with individual subclinical CVD measures, and multinomial logistic regression was used in analyses of the composite index. Models adjusted for socio-demographics and cardiovascular risk factors.

RESULTS

Mean age at subclinical CVD assessment was 60.2 years (SD ± 2.7). History of gestational hypertension/preeclampsia was associated with greater carotid IMT (β: 0.038, p = 0.004). Earlier age at first birth was associated with subclinical CVD, but not when accounting for CVD risk factors. History of gestational diabetes was associated with greater baPWV, but not related to our composite index.

CONCLUSIONS

Pregnancy history is an important marker of subclinical CVD in late midlife and may impact the vasculature through distinct pathways. Future studies are necessary to evaluate racial/ethnic differences in the observed associations and to assess the benefit of a composite subclinical CVD index for earlier CVD risk modification in midlife women.

Low-flow mediated constriction as a marker of endothelial function in healthy pregnancy and preeclampsia: A pilot study

OBJECTIVES

Overwhelming clinical evidence exists on disturbed vascular and endothelial function in the pathophysiology of preeclampsia (PE). In a non-pregnant (NP) population, L-FMC (low-flow mediated constriction) provides insight in the 'resting' endothelial capacity in contrast to the gold standard of flow mediated dilatation (FMD), reflecting endothelial nitric oxide bioavailability.

STUDY DESIGN

Longitudinal follow-up of 100 healthy pregnant (HP) women, 33 PE women and 16 NP controls with non-invasive vascular assessments. HP women were evaluated at 12 and 35 weeks of gestation and at 6 months postpartum. PE patients were assessed at diagnosis (mean 30 weeks) and 6 months postpartum.

MAIN OUTCOME MEASURES

Endothelial function (L-FMC, FMD, peripheral arterial tonometry (PAT)) and arterial stiffness (pulse wave velocity (PWV) and analysis (PWA)) were measured at the different visits and compared between groups.

RESULTS

Overall endothelial dysfunction is present in PE (FMD HP 9.09 ± 4.20 vs PE 5.21 ± 4.47, p = 0.0004; L-FMC HP -1.90 ± 2.66 vs PE -0.40 ± 2.09, p = 0.03). L-FMC gradually elevates during the course of a HP (1st trim -0.31 ± 1.75 vs 3rd trim -1.97 ± 3.02, p < 0.0001) and is present in 85% of women in the third trimester. In NP, only 27% of women has L-FMC. In PE, L-FMC is present in 50% of cases. Arterial stiffness is increased in PE (all p < 0.0001). There is no correlation between L-FMC and other markers of vascular function (p > 0.05).

CONCLUSION

PE is characterized by dysfunction of both resting and recruitable endothelial capacity. This study offers new insights in different aspects of endothelial function in pregnancy, since L-FMC reflects an adaptation in HP that is absent in PE.

Early and late preeclampsia are characterized by high cardiac output, but in the presence of fetal growth restriction, cardiac output is low: insights from a prospective study

BACKGROUND

Preeclampsia and fetal growth restriction are considered to be placentally mediated disorders. The clinical manifestations are widely held to relate to gestation age at onset with early- and late-onset preeclampsia considered to be phenotypically distinct. Recent studies have reported conflicting findings in relation to cardiovascular function, and in particular cardiac output, in preeclampsia and fetal growth restriction.

OBJECTIVE

We conducted this study to examine the possible relation between cardiac output and peripheral vascular resistance in preeclampsia and fetal growth restriction.

STUDY DESIGN

We investigated maternal cardiovascular function in relation to clinical subtype in 45 pathological pregnancies (14 preeclampsia only, 16 fetal growth restriction only, 15 preeclampsia and fetal growth restriction) and compared these with 107 healthy person observations. Cardiac output was the primary outcome measure and was assessed using an inert gas-rebreathing method (Innocor), from which peripheral vascular resistance was derived; arterial function was assessed by Vicorder, a cuff-based oscillometric device. Cardiovascular parameters were normalized for gestational age in relation to healthy pregnancies using Z scores, thus allowing for comparison across the gestational range of 24-40 weeks.

RESULTS

Compared with healthy control pregnancies, women with preeclampsia had higher cardiac output Z scores (1.87 ± 1.35; P = .0001) and lower peripheral vascular resistance Z scores (-0.76 ± 0.89; P = .025); those with fetal growth restriction had higher peripheral vascular resistance Z scores (0.57 ± 1.18; P = .04) and those with both preeclampsia and fetal growth restriction had lower cardiac output Z scores (-0.80 ± 1.3 P = .007) and higher peripheral vascular resistance Z scores (2.16 ± 1.96; P = .0001). These changes were not related to gestational age of onset. All those affected by preeclampsia and/or fetal growth restriction had abnormally raised augmentation index and pulse wave velocity. Furthermore, in preeclampsia, low cardiac output was associated with low birthweight and high cardiac output with high birthweight (r = 0.42, P = .03).

CONCLUSION

Preeclampsia is associated with high cardiac output, but if preeclampsia presents with fetal growth restriction, the opposite is true; both conditions are nevertheless defined by hypertension. Fetal growth restriction without preeclampsia is associated with high peripheral vascular resistance. Although early and late gestation preeclampsias are considered to be different diseases, we show that the hemodynamic characteristics of preeclampsia were unrelated to gestational age at onset but were strongly associated with the presence or absence of fetal growth restriction. Fetal growth restriction more commonly coexists with preeclampsia at early gestation, thus explaining the conflicting results of previous studies. Furthermore, antihypertensive agents act by reducing cardiac output or peripheral vascular resistance and are administered without reference to cardiovascular function in preeclampsia. The underlying pathology (preeclampsia, fetal growth restriction, preeclampsia and fetal growth restriction) defines cardiovascular phenotype, providing a rational basis for choice of therapy in which high or low cardiac output or peripheral vascular resistance is the predominant feature.