Effect of a nitric oxide donor on maternal hemodynamics in fetal growth restriction

Maternal Hemodynamics from Preconception to Delivery: Research and Potential Diagnostic and Therapeutic Implications: Position Statement by Italian Association of Pre-Eclampsia and Italian Society of Perinatal Medicine

OBJECTIVE

 The Italian Association of Preeclampsia (AIPE) and the Italian Society of Perinatal Medicine (SIMP) developed clinical questions on maternal hemodynamics state of the art.

STUDY DESIGN

 AIPE and SIMP experts were divided in small groups and were invited to propose an overview of the existing literature on specific topics related to the clinical questions proposed, developing, wherever possible, clinical and/or research recommendations based on available evidence, expert opinion, and clinical importance. Draft recommendations with a clinical rationale were submitted to 8th AIPE and SIMP Consensus Expert Panel for consideration and approval, with at least 75% agreement required for individual recommendations to be included in the final version.

RESULTS

 More and more evidence in literature underlines the relationship between maternal and fetal hemodynamics, as well as the relationship between maternal cardiovascular profile and fetal-maternal adverse outcomes such as fetal growth restriction and hypertensive disorders of pregnancy. Experts agreed on proposing a classification of pregnancy hypertension, complications, and cardiovascular states based on three different hemodynamic profiles depending on total peripheral vascular resistance values: hypodynamic (>1,300 dynes·s·cm-5), normo-dynamic, and hyperdynamic (<800 dynes·s·cm-5) circulation. This differentiation implies different therapeutical strategies, based drugs' characteristics, and maternal cardiovascular profile. Finally, the cardiovascular characteristics of the women may be useful for a rational approach to an appropriate follow-up, due to the increased cardiovascular risk later in life.

CONCLUSION

 Although the evidence might not be conclusive, given the lack of large randomized trials, maternal hemodynamics might have great importance in helping clinicians in understanding the pathophysiology and chose a rational treatment of patients with or at risk for pregnancy complications.

KEY POINTS

· Altered maternal hemodynamics is associated to fetal growth restriction.. · Altered maternal hemodynamics is associated to complicated hypertensive disorders of pregnancy.. · Maternal hemodynamics might help choosing a rational treatment during hypertensive disorders..

NO donors on top of anti-hypertensive therapy reduces complications in chronic hypertensive pregnancies with hypodynamic circulation

OBJECTIVES

Chronic hypertension is associated with significant adverse maternal and fetal outcomes that appear to be often associated to a hypodynamic circulation. Treatment of hypertensive disorders of pregnancy tailored on maternal hemodynamics might reduce or mitigate these complications. Our purpose was to assess the hemodynamic modifications induced by the addition of NO donors and increased oral fluid intake on top of standard antihypertensive therapy in hypodynamic chronic hypertensive patients. We further evaluated if the possible hemodynamic modification induced by NO donors and increased oral fluid intake might be associated to a reduction of the severity and rate of complications vs. patients on antihypertensive standard treatment.

STUDY DESIGN

This was a case-control study of 321 chronic hypertensive patients with a hypodynamic circulation at the echocardiographic evaluation at 24 weeks' gestation. We included 160 controls (standard antihypertensive therapy) and 161 cases (standard therapy + NO donor patches + increased oral fluid intake). Student T test for paired and unpaired data, univariate logistic regression analysis, ROC curve analysis, and Cox Hazards Regression analysis were used as appropriate.

RESULTS

At enrollment the hemodynamic parameters were similar between the two groups. After 3-4 weeks stroke volume (77 ± 19 mL vs. 69 ± 19 mL; p < 0.001), and cardiac output (6.2 ± 1.7 L vs. 5.0 ± 1.6 L; p < 0.001) were higher and total peripheral vascular resistance (1465 ± 469 dyne·s·cm-5 vs. 1814 ± 524 dyne·s·cm-5; p < 0.001) was lower in the cases vs controls. Superimposed preeclampsia, preterm delivery before 34 weeks, abruptio placentae, HELLP Syndrome, fetal growth restriction, and perinatal death were more represented in the standard treatment group vs NO treated patients (81% vs 53%; p < 0.001). In particular, the standard treatment group showed 48% fetal growth restriction vs 34% in the NO treated group (p < 0.011). The Cox proportional-hazards regression showed a lower proportion of event-free pregnancies in controls on standard treatment (HR 2.6; 95% CI 2.0-3.5; p < 0.0001), and a prolongation of pregnancies in CH cases complicated by fetal growth restriction taking NO donors (HR 0.29; 95% CI 0.19-0.43; p = 0.0001).

CONCLUSIONS

The tailored treatment with NO donors and oral fluids of hypodynamic CH might have positive effects on the reduction or mitigations of adverse outcomes.

Maternal hemodynamic profile during pregnancy and in the post-partum in hypertensive disorders of pregnancy and fetal growth restriction

BACKGROUND

Maternal cardiovascular changes, occurring since the beginning of pregnancy, are necessary for normal placentation and regular evolution of pregnancy.

OBJECTIVE

This study aimed to compare the hemodynamic profiles and cardiac remodeling of women with hypertensive disorders of pregnancy and either appropriate for gestational age fetuses or growth-restricted fetuses, women with normotensive pregnancies complicated by fetal growth restriction, and women with uncomplicated pregnancies, during pregnancy and the postpartum period.

STUDY DESIGN

A prospective longitudinal case-control design was used for this study. Over the study period, 220 eligible women with singleton pregnancies were selected for the analysis and divided into 4 groups: (1) hypertensive disorders of pregnancy with appropriate for gestational age fetuses; (2) hypertensive disorders of pregnancy with fetal growth restriction; (3) normotensive fetal growth restriction; and (4) controls. Ultrasound fetal biometry and fetoplacental Doppler velocimetry were performed at recruitment. Maternal hemodynamic assessment using transthoracic echocardiography was performed at the time of recruitment by a dedicated cardiologist blinded to maternal clinical data. The same assessments were performed in 104 patients at 32 weeks (interquartile range, 24-40) after delivery by the same cardiologist.

RESULTS

During pregnancy, women in the hypertensive-disorders-of-pregnancy-fetal-growth-restriction group showed significantly lower cardiac output and increased compared with those in the control group. These values were associated with concentric remodeling of the left ventricle owing to relatively increased wall thickness, which was not accompanied by an increase in left ventricular mass. Isolated fetal growth restriction presented similar but less important hemodynamic changes; however, there was no change in relative wall thickness. At postpartum follow-up, the hemodynamic parameters of women in the hypertensive-disorders-of-pregnancy-fetal-growth-restriction and isolated-fetal-growth-restriction groups reverted to values similar to those of the control group. Only 8.3% of women in these groups experienced hypertension even in the postpartum period, and asymptomatic stage-B cardiac failure was observed for 17% at echocardiography. In the group of women with hypertensive disorders of pregnancy and appropriate for gestational age fetuses, cardiac output increased as in normal pregnancies, but total vascular resistance was significantly higher; hypertension then occurred, along with ventricular concentric hypertrophy and diastolic dysfunction. At postpartum follow-up, women in the hypertensive-disorders-of-pregnancy-appropriate-for-gestational-age-fetus group showed significantly higher mean arterial pressure, total vascular resistance, and left ventricular mass compared with those in the control group. Persistent hypertension and asymptomatic stage-B cardiac failure were observed in 39.1% and 13% of women in the former group, respectively.

CONCLUSION

Pregnancies with hypertensive disorders of pregnancy and fetal growth restriction and normotensive pregnancies with fetal growth restriction were associated with the hemodynamic profile of lower heart rate and cardiac output, most likely because of abnormal adaptation to pregnancy, as confirmed by abnormal changes from pregnancy to the postpartum period. The heart rates and cardiac output of women in the hypertensive-disorders-of-pregnancy-appropriate-for-gestational-age-fetus group showed changes opposite to those observed in the hypertensive-disorders-of-pregnancy-fetal-growth-restriction and fetal-growth-restriction groups. Obesity and other metabolic risk factors, significantly prevalent in women in the hypertensive-disorders-of-pregnancy-appropriate-for-gestational-age-fetus group, predispose to hypertension and cardiovascular diseases during pregnancy and the postpartum period, potentially offering a window for personalized prevention. Such preventive strategies could differ in women with hypertensive disorders of pregnancy and fetal growth restriction characterized by poor early placental development.

The cardiac-fetal-placental unit: fetal umbilical vein flow rate is linked to the maternal cardiac profile in fetal growth restriction

BACKGROUND

The functional maternal-fetal hemodynamic unit includes fetal umbilical vein flow and maternal peripheral vascular resistance.

OBJECTIVE

This study investigated the relationships between maternal and fetal hemodynamics in a population with suspected fetal growth restriction.

STUDY DESIGN

This was a prospective study of normotensive pregnancies referred to our outpatient clinic for a suspected fetal growth restriction. Maternal hemodynamics measurement was performed, using a noninvasive device (USCOM-1A) and a fetal ultrasound evaluation to assess fetal biometry and velocimetry Doppler parameters. Comparisons among groups were performed with 1-way analysis of variance with Student-Newman-Keuls correction for multiple comparisons and with Kruskal-Wallis test where appropriate. The Spearman rank coefficient was used to assess the correlation between maternal and fetal hemodynamics. Pregnancies were observed until delivery.

RESULTS

A total of 182 normotensive pregnancies were included. After the evaluation, 54 fetuses were classified as growth restricted, 42 as small for gestational age, and 86 as adequate for gestational age. The fetus with fetal growth restriction had significantly lower umbilical vein diameter (P<.0001), umbilical vein velocity (P=.02), umbilical vein flow (P<.0001), and umbilical vein flow corrected for fetal weight (P<.01) than adequate-for-gestational-age and small-for-gestational-age fetuses. The maternal hemodynamic profile in fetal growth restriction was characterized by elevated systemic vascular resistance and reduced cardiac output. The umbilical vein diameter was positively correlated to maternal cardiac output (r_s=0.261), whereas there was a negative correlation between maternal systemic vascular resistance (r_s=-0.338) and maternal potential energy-to-kinetic energy ratio (r_s=-0267). The fetal umbilical vein time averaged max velocity was positively correlated to maternal cardiac output (r_s=0.189) and maternal inotropy index (r_s=0.162), whereas there was a negative correlation with maternal systemic vascular resistance (r_s=-0.264) and maternal potential energy-to-kinetic energy ratio (r_s=-0.171). The fetal umbilical vein flow and the flow corrected for estimated fetal weight were positively correlated with maternal cardiac output (r_s=0.339 and r_s=0.297) and maternal inotropy index (r_s=0.217 and r=0.336), whereas there was a negative correlation between maternal systemic vascular resistance (r_s=-0.461 and r_s=-0.409) and maternal potential energy-to-kinetic energy ratio (r_s=-0.336 and r_s=-0.408).

CONCLUSION

Maternal and fetal hemodynamic parameters were different in the 3 groups of fetuses: fetal growth restriction, small for gestational age, and adequate for gestational age. Maternal hemodynamic parameters were closely and continuously correlated with fetal hemodynamic features. In particular, a maternal hemodynamic profile with high systemic vascular resistance, low cardiac output, reduced inotropism, and hypodynamic circulation was correlated with a reduced umbilical vein flow and increased umbilical artery pulsatility index. The mother, placenta, and fetus should be considered as a single cardiac-fetal-placental unit. The correlations of systemic vascular resistance, cardiac output, and inotropy index with umbilical artery impedance indicate the key role of these 3 parameters in placental vascular tree development. The umbilical vein flow rate and, therefore, the placental perfusion seems to be influenced not only by these three parameters but also by the maternal cardiovascular kinetic energy.

An update on maternal cardiac hemodynamics in fetal growth restriction and pre-eclampsia

Pre-eclampsia and fetal growth restriction (FGR) have been long related to primary placental dysfunction, caused by abnormal trophoblast invasion. Nevertheless, emerging evidence has led to a new hypothesis for the origin of pre-eclampsia and FGR. Suboptimal maternal cardiovascular adaptation has been shown to result in uteroplacental hypoperfusion, ultimately leading to placental hypoxic damage with secondary dysfunction. In this review, we summarize current evidence on maternal cardiac hemodynamics in FGR and pre-eclampsia. We also discuss the different approaches for antihypertensive treatment according to the hemodynamic phenotype observed in pre-eclampsia and FGR.

Maternal Low Volume Circulation Relates to Normotensive and Preeclamptic Fetal Growth Restriction

This narrative review summarizes current evidence on the association between maternal low volume circulation and poor fetal growth. Though much work has been devoted to the study of cardiac output and peripheral vascular resistance, a low intravascular volume may explain why high vascular resistance causes hypertension in women with preeclampsia (PE) that is associated with fetal growth restriction (FGR) and, at the same time, presents with normotension in FGR itself. Normotensive women with small for gestational age babies show normal gestational blood volume expansion superimposed upon a constitutionally low intravascular volume. Early onset preeclampsia (EPE; occurring before 32 weeks) is commonly associated with FGR, and poor plasma volume expandability may already be present before conception, thus preceding gestational volume expansion. Experimentally induced low plasma volume in rodents predisposes to poor fetal growth and interventions that enhance plasma volume expansion in FGR have shown beneficial effects on intrauterine fetal condition, prolongation of gestation and birth weight. This review makes the case for elevating the maternal intravascular volume with physical exercise with or without Nitric Oxide Donors in FGR and EPE, and evaluating its role as a potential target for prevention and/or management of these conditions.

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.

Educational Review: The Impact of Perinatal Oxidative Stress on the Developing Kidney

Oxidative stress occurs when there is an imbalance between reactive oxygen species/reactive nitrogen species and antioxidant systems. The interplay between these complex processes is crucial for normal pregnancy and fetal development; however, when oxidative stress predominates, pregnancy related complications and adverse fetal programming such as preterm birth ensues. Understanding how oxidative stress negatively impacts outcomes for the maternal-fetal dyad has allowed for the exploration of antioxidant therapies to prevent and/or mitigate disease progression. In the developing kidney, the negative impact of oxidative stress has also been noted as it relates to the development of hypertension and kidney injury mostly in animal models. Clinical research addressing the implications of oxidative stress in the developing kidney is less developed than that of the neurodevelopmental and respiratory conditions of preterm infants and other vulnerable neonatal groups. Efforts to study the oxidative stress pathway along the continuum of the perinatal period using a team science approach can help to understand the multi-organ dysfunction that the maternal-fetal dyad sustains and guide the investigation of antioxidant therapies to ameliorate the global toxicity. This educational review will provide a comprehensive and multidisciplinary perspective on the impact of oxidative stress during the perinatal period in the development of maternal and fetal/neonatal complications, and implications on developmental programming of accelerated aging and cardiovascular and renal disease for a lifetime.

Maternal hemodynamic changes in gestational diabetes: a prospective case-control study

PURPOSE

The aim of the study is to compare maternal hemodynamic adaptations in gestational diabetes (GDM) versus healthy pregnancies.

METHODS

A prospective case-control study was conducted, comparing 69 singleton pregnancies with GDM and 128 controls, recruited between September 2018 and April 2019 in Maternal-Fetal Medicine Unit, Careggi University Hospital, Florence, Italy. Hemodynamic assessment by UltraSonic Cardiac Output Monitor (USCOM) was performed in both groups in four gestational age intervals: 17-20 weeks (only in early GDM cases), 26-30 weeks, 32-35 weeks and 36-39 weeks. We evaluated six hemodynamic parameters comparing GDM cases versus controls: cardiac output (CO), cardiac index (CI), stroke volume (SV), total vascular resistance (TVR), inotropy index (INO) and potential to kinetic energy ratio (PKR).

RESULTS

GDM group had significantly lower values of CO and SV than controls from the early third trimester (26-30 weeks) until term (p < 0.001). CI is significantly lower in GDM women already at the first evaluation (p = 0.002), whereas TVR and PKR were significantly higher in GDM (p < 0.001). GDM women showed also lower INO values than controls in all assessments.

CONCLUSIONS

A hemodynamic maternal maladaptation to pregnancy can be detected in GDM women. The effect of hyperglycemia on vascular system or a poor pre-pregnancy cardiovascular (CV) reserve could explain this hemodynamic maladaptation. The abnormal CV response to pregnancy in GDM women may reveal a predisposition to develop CV disease later in life and might help in identifying patients who need a CV follow-up.

Fetal Growth Restriction: Does an Integrated Maternal Hemodynamic-Placental Model Fit Better?

In recent years, a growing interest has arisen regarding the possible relationship between adverse pregnancy outcomes (APOs) and inadequate maternal hemodynamic adaptations to the pregnancy. A possible association between "placental syndromes," such as preeclampsia (PE) and fetal growth restriction (FGR), and subsequent maternal cardiovascular diseases (CVD) later in life has been reported. The two subtypes of FGR show different pathogenetic and clinical features. Defective placentation, due to a poor trophoblastic invasion of the maternal spiral arteries, is believed to play a central role in the pathogenesis of early-onset PE and FGR. Since placental functioning is dependent on the maternal cardiovascular system, a pre-existent or subsequent cardiovascular impairment may play a key role in the pathogenesis of early-onset FGR. Late FGR does not seem to be determined by a primary abnormal placentation in the first trimester. The pathological pathway of late-onset FGR may be due to a primary maternal cardiovascular maladaptation: CV system shows a flat profile and remains similar to those of non-pregnant women. Since the second trimester, when the placenta is already developed and increases its functional request, a hypovolemic state could lead to placental hypoperfusion and to an altered maturation of the placental villous tree and therefore to an altered fetal growth. Thus, this review focalizes on the possible relationship between maternal cardiac function and placentation in the development of both early and late-onset FGR. A better understanding of maternal hemodynamics in pregnancies complicated by FGR could bring various benefits in clinical practice, improving screening and therapeutic tools.

What is the role of glycemic control in the development of preeclampsia among women with type 1 diabetes?

OBJECTIVE

To investigate the role of glycemic control in development of preeclampsia (PE) in women with type 1 diabetes mellitus (T1DM).

METHODS

An observational case-control study comparing 244 women with type 1 diabetes and 488 controls was conducted. Among women with T1DM HbA1c, average daily glucose values, fasting, preprandial, 1-hour and 2-hour postprandial glucose levels, and daily 3 meals postprandial glucose areas were evaluated. Uterine artery pulsatility indices (PI) at 16, 20, 24 weeks' gestation were obtained. Data analysis included rates of PE in both groups, and association between glycemic control, uterine artery PI and development of PE among women with T1DM.

RESULTS

PE developed in 13.1% of diabetic women and in 3.5% of women in the control group (odds ratio 4.2; 95% CI 2.2-8.1). In multivariate logistic regression analysis, HbA1c in the 1st trimester, mean daily glucose level in the 1st and 2nd trimester, daily 3 meal postprandial glucose area in the 1st and 2nd trimester, and the uterine arteries PI at 24 weeks' gestation were found to be associated with development of PE. The uterine arteries PI showed a significant positive correlation with the 3 meal postprandial glucose area at 16, 20, 24 weeks.

CONCLUSION

In women with T1DM, poor glycemic control early in pregnancy is associated with an increased risk of subsequent PE. An association between poor placentation, as indicated by the increased PI of uterine arteries, and a maternal metabolic factor, that is the 3 meal post-prandial glucose area, has been shown, supporting the increased rate of PE among women with T1DM.

Treatment of pregnancies complicated by intrauterine growth restriction with nitric oxide donors increases placental expression of Epidermal Growth Factor-Like Domain 7 and improves fetal growth: A pilot study

Intrauterine growth restriction (IUGR) is a pathological condition of pregnancy with high perinatal mortality and morbidity, characterized by inadequate fetal growth associated to altered maternal hemodynamics with impaired uteroplacental blood flow and placental insufficiency. To date, iatrogenic premature delivery remains the elective therapeutic strategy. However, in recent years the possibility of a therapeutic approach with vasodilators and myorelaxants, such as nitric oxide (NO) donors, has gained interest. NO controls many endothelial cell functions, including angiogenesis and vascular permeability, by regulating the expression of angiogenic factors, such as Vascular Endothelial Growth Factor. In the present study, we investigated if treatment of pregnancies complicated by IUGR with NO donors affects the expression of Epidermal Growth Factor-Like Domain 7 (EGFL7), a secreted endothelial factor, previously demonstrated to be expressed by both endothelial and trophoblast cells and involved in proper placental development. NO donor treatment induced placental levels of EGFL7 and, in association with oral fluids, significantly improved fetal growth. Ex vivo experiments confirmed that NO donors increased expression and secretion of EGFL7 by villous explants. To specifically investigate the potential response of trophoblast cells to NO, we treated HTR8-sVneo cells with NO donors and observed induction of EGFL7 expression. Altogether, our findings indicate that NO induces endothelial and trophoblast expression of EGFL7 in the placenta and improves fetal growth, suggesting a correlation between placental levels of EGFL7 and pregnancy outcome.

Potential effects of transdermal nitric oxide donor on fetal growth restriction and oligohydramnios: A case report

Transdermal nitric oxide donor may be a relatively safe treatment strategy for fetal growth restriction and oligohydramnios due to placental insufficiency.

The impact of obesity on haemodynamic profiles of pregnant women beyond 34 weeks' gestation

OBJECTIVE

We aimed to compare the haemodynamic profiles of obese and non-obese pregnant women, alongside describing the haemodynamic changes that occur in hypertensive disorders of pregnancies with an Appropriate for Gestational Age Fetus (HDP-AGA) beyond 34 weeks' gestation.

STUDY DESIGN

In this prospective case-control study, maternal haemodynamic assessment was carried out by a trained operator using an UltraSonic Cardiac Output Monitor during a routine clinical assessment after 34 weeks of gestation. Indexed and non-indexed parameters were evaluated.

MAIN OUTCOME MEASURES

Maternal hemodynamic parameters.

RESULTS

Obese and non-obese women did not differ for non-indexed parameters (Cardiac Output, Stroke Volume, Systemic Vascular Resistance). Using indexed parameters, corrected for Body Surface Area, obese women presented significantly lower Cardiac Index z-score (-0.23 ± 0.5 vs 0.26 ± 1.2; p = 0.004), Stroke Volume Index z-score (-0.27 ± 0.8 vs 0.31 ± 1.0; p < 0.0001) and significantly higher Systemic Vascular Resistance Index (0.16 ± 0.8 vs -0.36 ± 0.7; p < 0.0001). In obese women, HDP-AGA (n = 19) had significantly higher Systemic Vascular Resistance Index z-score (1.26 ± 1.7 vs 0.16 ± 0.8; P = 0.009) and significantly lower Stroke Volume Index (-0.68 ± 0.8 vs -0.27 ± 0.8; 0.049).

CONCLUSION

Using indexed parameters, differences in haemodynamic profiles between obese and non obese women can be highlighted. Obese women seem to present a cardiac maladapation to the pregnancy (reduced cardiac index and stroke volume and increased vascular resistance) that could explain the increased risk of complications in this subgroup.

Hemodynamic maladaptation and left ventricular dysfunction in chronic hypertensive patients at the beginning of gestation and pregnancy complications: a case control study

OBJECTIVE

The aim of this study was to evaluate early pregnancy differences in maternal hemodynamics, cardiac geometry and function, between chronic hypertensive (CH) patients with and without the development of feto-maternal complications later in pregnancy.

METHODS

We performed a case-control study on nulliparous CH treated patients. From a group of CH patients referred to our outpatient clinic at 4-6 weeks for a clinical evaluation the first consecutive 30 patients with subsequent complications (superimposed PE, abruptio placentae, uncontrolled severe hypertension with delivery <34 weeks, HELLP syndrome, FGR, perinatal death) were enrolled; the first 2 CH women with uneventful pregnancy referred after the case were enrolled as controls for a total of 60 patients. All patients were shifted to alpha-methyl dopa at the beginning of pregnancy and were submitted to an echocardiographic evaluation to assess the maternal hemodynamics, cardiac geometry, diastolic and systolic function.

RESULTS

Patients developing complications had a lower early pregnancy heart rate (73 ± 11 vs. 82 ± 11 bpm), cardiac output (5.23 ± 1.2 vs. 6.5 ± 1.3 L/min, p<.01) and cardiac index (3.0 ± 0.7 vs. 3.6 ± 0.7 L/min/m², p<.01); higher total vascular resistance (1554 ± 305 vs. 1248 ± 243 d.s.cm^-5, p<.01) and total vascular resistance index (2666 ± 519 vs. 2335 ± 431, d.s.cm^-5/m², p<.01); higher left ventricular mass index (42.1 ± 8.6 vs. 36.9 ± 8.3 g/m², p<.01) and relative wall thickness (0.40 ± 0.05 vs. 0.36 ± 0.05, p<.01) of the left ventricle, resulting in a higher prevalence of altered cardiac geometry vs. uneventful CH controls. Diastolic and systolic dysfunction were also present with a higher E/e' ratio (10.50 ± 3.56 vs. 7.22 ± 1.91, p<.01) and a lower stress corrected midwall mechanics (89 ± 21 vs. 100 ± 22, p=.02) of the left ventricle.

CONCLUSION

CH treated patients developing maternal and/or fetal complications show early pregnancy altered cardiac geometry, diastolic and systolic dysfunction, and impaired hemodynamics with a high resistance circulation.

Maternal Cardiovascular Dysfunction is Associated with Hypoxic Cerebral and Umbilical Doppler Changes

We investigate the relationship between maternal cardiovascular (CV) function and fetal Doppler changes in healthy pregnancies and those with pre-eclampsia (PE), small for gestational age (SGA) or fetal growth restriction (FGR). This was a three-centre prospective study, where CV assessment was performed using inert gas rebreathing, continuous Doppler or impedance cardiography. Maternal cardiac output (CO) and peripheral vascular resistance (PVR) were analysed in relation to the uterine artery, umbilical artery (UA) and middle cerebral artery (MCA) pulsatility indices (PI, expressed as z-scores by gestational week) using polynomial regression analyses, and in relation to the presence of absent/reversed end diastolic (ARED) flow in the UA. We included 81 healthy controls, 47 women with PE, 65 with SGA/FGR and 40 with PE + SGA/FGR. Maternal CO was inversely related to fetal UA PI and positively related to MCA PI; the opposite was observed for PVR, which was also positively associated with increased uterine artery impedance. CO was lower (z-score 97, p = 0.02) and PVR higher (z-score 2.88, p = 0.02) with UA ARED flow. We report that maternal CV dysfunction is associated with fetal vascular changes, namely raised impedance in the fetal-placental circulation and low impedance in the fetal cerebral vessels. These findings are most evident with critical UA Doppler changes and represent a potential mechanism for therapeutic intervention.

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

BACKGROUND

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Maternal Hypertension, Advanced Doppler Haemodynamics and Therapeutic Precision: Principles and Illustrative Cases

PURPOSE OF REVIEW

Maternal hypertension is a common and serious condition associated with increased maternal and foetal morbidity and mortality, with early detection and management improving outcomes.

RECENT FINDINGS

Blood pressure (BP) changes of pre-eclampsia are defined after 20 gestational weeks, while haemodynamic changes can be detected at 5-11 weeks using a specialised non-invasive Doppler stroke volume (SV) monitor. Thus, advanced haemodynamic monitoring allows for physiologically precise identification of circulatory abnormalities, and implementation of appropriate therapy within the first trimester. We measured the oscillometric BP and advanced haemodynamics (USCOM 1A) of 3 unselected women with singleton pregnancies, consecutively listed for therapeutic induction for maternal hypertension at 32-41 weeks gestational age. While the BP's of the patients varied, it was the haemodynamics, particularly SV, cardiac output, systemic vascular resistance, Smith Madigan Inotropy Index, and oxygen deliver, that identified differing patterns of circulatory dysfunction, therapeutic objectives, and predicted post-partum complications of the mother and child. First trimester screening of maternal haemodynamics may allow for earlier detection of circulatory derangements, selection of patient precise interventions, and improved maternal-foetal outcomes.

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.

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

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