Maternal cardiovascular function at mid-gestation is related to placental angiogenesis

OBJECTIVE

To investigate whether placental function, reflected in the levels of angiogenic factors, is associated with maternal cardiac function and hemodynamic responses at 19 to 24 weeks' gestation after adjustment for maternal risk factors and pregnancy complications.

METHODS

Prospective study on women with singleton pregnancies attending Kings' College Hospital, London, UK for a routine hospital visit at 19-24 weeks' gestation. We recorded maternal characteristics and measured mean arterial pressure, maternal heart rate, serum placental growth factor and soluble fms-like tyrosine kinase 1 (sFLT-1). We also performed maternal echocardiogram to assess cardiac output and peripheral vascular resistance as well as indices of diastolic and systolic function.

RESULTS

Our cohort included 4006 women. Lower placental growth factor (PlGF) values were significantly associated with higher mean arterial pressure (MAP) (p<0.001), lower maternal heart rate (p<0.001), lower mitral valve s' velocity (p= 0.027) and higher left atrial volume (p=0.022) after adjustment for maternal characteristics and pregnancy complications. sFLT-1 was positively related to relative wall thickness (p= 0.012), whereas sFLT-1/ PlGF ratio was negatively associated with mitral valve A (p= 0.006) and positively associated with left atrial volume (p= 0.015) and MAP (p= 0.004). The magnitude of these associations was similar in the subgroup of women without any risk factors from their obstetric and medical history.

CONCLUSION

A continuous link of moderate strength between angiogenic factors and subclinical maternal cardiac function alterations is present at mid-gestation, independently of preexisting maternal risk factors and pregnancy complications. Impaired placental function appears to be related to a mild systolic and diastolic dysfunction and cardiac remodeling. This article is protected by copyright. All rights reserved.

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 hemodynamics for the identification of early fetal growth restriction in normotensive pregnancies

We aimed at testing systemic vascular resistance (SVR) for the correct identification of early fetal growth restriction (FGR). 61 normotensive patients, gestational age 29 + 0-32 + 0, with suspected diagnosis of early FGR, were submitted to USCOM and to an ultrasound evaluation. 24 patients met the criteria of FGR, and 9 patients developed umbilical artery Doppler alterations. SVR>1006 dyn s·cm^-5 correctly identified patients with a subsequent diagnosis of FGR, whereas SVR>1222 dyn s·cm^-5 was related to FGR with subsequent umbilical artery Doppler alterations. These data might be important to introduce USCOM in the clinical practice to identify and treat FGR.

Hemodynamic assessment in patients with preterm premature rupture of the membranes (pPROM)

OBJECTIVE

The aim of this study was to assess the hemodynamic differences in women with pPROM versus physiological pregnancies.

STUDY DESIGN

This was a prospective case control study of 15 patients with pPROM and 45 controls. Patients and controls were submitted at enrollment to a non-invasive hemodynamic evaluation with UltraSonic Cardiac Output Monitor (USCOM), and to blood tests to check white blood cells count and C-reactive protein (CRP) levels. We followed pPROM patients until delivery noting fetal/neonatal and maternal unfavorable outcomes (maternal fever, APGAR 1' and 5'< 7, stillbirth).

RESULTS

Patients with pPROM showed higher values of cardiac output (9.1 ± 2.3 vs 7.1 ± 0.85, p < 0.01), lower systemic vascular resistances (792.1 ± 162 vs 1006.2 ± 110.7, p < 0.01), higher minute distance (32.3 ± 7.8 vs 25 ± 2.8, p < 0.01), lower Potential to Kinetic Energy Ratio (16.5 ± 5.3 vs 22.4 ± 6.8, p < 0.01), higher heart rate (97.5 ± 15.4 vs 82.4 ± 12, p < 0.01) and higher oxygen delivery (1313.2 ± 325.8 vs 1080.7 ± 151.8, p < 0.01) vs. controls. Six out of 15 pPROM patients had an unfavorable outcome. There were no significant differences in CRP levels and WBC count at admission in the two pPROM subgroups, whereas maternal hemodynamics was characterized by lower SVR (718 ± 72 vs 863 ± 123, p = 0.02) in subsequently complicated patients.

CONCLUSIONS

Maternal hemodynamics is altered in pPROM patients, with a lower Systemic Vascular Resistance and higher Cardiac Output vs. controls. This hyperdynamic circulation appears to anticipates the changes of serum markers of inflammation (CRP, WBC count) and seems to be more pronounced at admission in pPROM patients developing unfavorable outcomes.

Hypertensive disorders and maternal hemodynamic changes in pregnancy: monitoring by USCOM® device

Hypertensive disorders are quite common, complicating about 10% of pregnancies, while preeclampsia occurs in 2-8% of cases. The most recognized etiopathogenetic factor for the development of preeclampsia is deficient remodeling of the spiral arteries during trophoblastic invasion. Recently, some authors speculated about the "cardiovascular origin of preeclampsia"; in particular, they postulate that placental dysfunction is not the primum movens of preeclampsia, but it could be caused by a failure of the maternal cardiovascular system to adapt to the pregnancy itself. Moreover, several studies have also shown that developing preeclampsia in pregnancy is associated with an increased risk of cardiovascular disease later in life. Due to the importance of this pathology, it would be crucial to have an effective screening in order to implement a prophylaxis; for this purpose, it could be useful to have an accurate and noninvasive device for the assessment of maternal hemodynamic variables. USCOM^® (Ultrasonic Cardiac Output Monitor) is a noninvasive Doppler ultrasonic technology which combines accuracy, reproducibility, noninvasiveness, and a fast learning curve. Maternal hemodynamic evaluation is important in order to monitor the changes that the maternal organism encounters, in particular a reduction in blood pressure, a decrease in total peripheral resistances, and an increase in cardiac output, resulting in a hyperdynamic circle. These hemodynamic modifications are lacking in pregnancies complicated by preeclampsia. For these reasons, it is crucial to have a tool that allows these parameters to be easily evaluated in order to identify those women at higher risk of hypertensive complications and more severe outcomes.

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.

Association between thyroid-stimulating hormone and maternal hemodynamics in hypertensive disorders of pregnancy: an observational study

Background

Hypertensive disorders of pregnancy (HDP) are characterized by hemodynamic disturbances. Altered thyroid function is a risk factor for poor outcomes of pregnancy. However, the associations between thyroid function biomarkers and maternal hemodynamics during pregnancy in HDP remain unclear.

Methods

From January 2016 to January 2018, pregnant women diagnosed with HDP admitted to the Nanjing Maternity and Child Health Care Hospital were prospectively enrolled in the third trimester. Normally distributed variables were expressed as mean ± standard deviation and skewed variables were expressed as median (25th percentile, 75th percentile). Correlations between thyroid-stimulating hormone (TSH) or free thyroxine (FT4) and maternal hemodynamic parameters were assessed by Pearson’s correlation coefficient and 95% confidence interval (95%CI). Bonferroni’s correction for multiple correlations was performed. Logistic regression models with odd ratio (OR) and 95%CI were applied to confirm the associations.

Results

A total of 163 third-trimester pregnant women with HDP with a mean gestational age of 35.62 ± 2.83 weeks were recruited. The infant birth weight of patients with elevated TSH levels was lower than that of patients with normal TSH levels (2635 ± 867 g vs. 3037 ± 673 g, p = 0.002). Reduced cardiac output (CO) was defined as CO < 3.5 L/min. The infant birth weight of patients with reduced CO was lower than that of patients with normal CO (2250 ± 510 g vs. 2890 ± 774 g, p = 0.002). TSH levels were significantly and negatively correlated with CO (r = − 0.260, 95%CI: − 0.392- -0.103, p < 0.001). FT4 levels were not significantly correlated with any of the maternal hemodynamic parameters (all p > 0.05). TSH level (OR = 1.371, 95%CI: 1.086–1.733, p = 0.008) was confirmed associated with reduced CO in the logistic regression analysis.

Conclusions

Elevated TSH levels are associated with reduced CO in HDP during the third trimester.

Low Volume Circulation in Normotensive Women Pregnant with Neonates Small for Gestational Age

BACKGROUND

Pregnancies complicated with small for gestational age (SGA) neonates are reported with maternal circulatory maladaptations.

OBJECTIVES

We aimed to understand the pathophysiology of the maternal circulation in normotensive SGA pregnancies and to point out the trimestral differences from those with appropriate-to-large (non-SGA [NGA]) neonates.

METHODS

An observational study was conducted in 3 trimestral cohorts of normotensive pregnancies, categorized after birth according to neonatal birth weight percentile (BW%) as SGA (BW% ≤10, n = 158) or NGA (BW% > 10, n = 1,038). Standardized electrocardiogram-Doppler ultrasound, impedance cardiography, and bio-impedance were used to assess the maternal heart, arteries, veins, and fluid.

RESULTS

Diastolic blood pressure and mean arterial pressure were not significantly different, unless in the third trimester. In SGA compared to NGA pregnancies, total peripheral resistance (TPR) was higher and total arterial compliance, cardiac output (CO), and total body water (TBW) were lower throughout pregnancy. Venous return-enhancing functions were activated. In NGA but not SGA pregnancies, a positive correlation was found between BW% and CO + TBW and a negative correlation between BW% and TPR.

CONCLUSIONS

SGA pregnancies are characterized by lower maternal body fluid volume and CO, while normal blood pressures are maintained via increased TPR already from the first trimester onwards. Pregnancy-induced hemodynamic changes are superimposed on these characteristics.

Cardiovascular Sequels During and After Preeclampsia

Preeclampsia is a pregnancy-specific disorder complicating 2%-8% of pregnancies worldwide and characterized by de novo development of hypertension and proteinuria. Current understanding of the pathophysiology of preeclampsia is limited. A main feature is disrupted spiral artery remodeling in the placenta, which restricts the blood flow to the placenta, which in turn leads to decreased uteroplacental perfusion. Impaired blood flow through the placenta might result in fetal growth restriction and secretion of several factors by the placenta-mainly pro-inflammatory cytokines and anti-angiogenic factors-which spread into the maternal circulation, leading to endothelial dysfunction, which subsequently results in disrupted maternal hemodynamics. To date, no treatment options are available apart from termination of pregnancy. Despite normalization of the maternal vascular disturbances after birth, it has become apparent that formerly preeclamptic women experience an increased risk to develop cardiovascular and kidney disease later in life. One well-accepted concept is that the development of preeclampsia is an indicator of maternal susceptibility to develop future cardiovascular conditions, although the increased risk might also be the result of organ damage caused during preeclampsia. Given the associations between preeclampsia and long-term complications, preeclampsia is acknowledged as woman-specific risk factor for cardiovascular disease. Current research focuses on finding effective screening and prevention strategies for the reduction of cardiovascular disease in women with a history of preeclampsia.

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.