Hemodynamic Adaptation during Pregnancy in Chronic Hypertension

The extent of postpartum cardiac reverse remodeling is reflected in urine proteome

The association of postpartum cardiac reverse remodeling (RR) with urinary proteome, particularly in pregnant women with cardiovascular (CV) risk factors who show long-term increased risk of cardiovascular disease and mortality is unknown. We aim to profile the urinary proteome in pregnant women with/without CV risk factors to identify proteins associated with postpartum RR. Our study included a prospective cohort of 32 healthy and 27 obese and/or hypertensive and/or diabetic pregnant women who underwent transthoracic echocardiography, pulse-wave-velocity, and urine collection at the 3rd trimester and 6 months postpartum. Shotgun HPLC-MS/MS profiled proteins. Generalized linear mixed-effects models were used to identify associations between urinary proteins and left ventricle mass (LVM), a surrogate of RR. An increase in arterial stiffness was documented from 3rd trimester to 6 months after delivery, being significantly elevated in women with CV risk factors. In addition, the presence of at least one CV risk factor was associated with worse LVM RR. We identified 6 and 11 proteins associated with high and low LVM regression, respectively. These proteins were functionally linked with insulin-like growth factor (IGF) transport and uptake regulation by IGF binding-proteins, platelet activation, signaling and aggregation and the immune system's activity. The concentration of IGF-1 in urine samples was associated with low LVM regression after delivery. Urinary proteome showed a predicting potential for identifying pregnant women with incomplete postpartum RR.

Stretch-induced compliance mechanism in pregnancy-induced cardiac hypertrophy and the impact of cardiovascular risk factors

Pressure overload-induced hypertrophy compromises cardiac stretch-induced compliance (SIC) after acute volume overload (AVO). We hypothesized that SIC could be enhanced by physiological hypertrophy induced by pregnancy's chronic volume overload. This study evaluated SIC-cardiac adaptation in pregnant women with or without cardiovascular risk (CVR) factors. Thirty-seven women (1st trimester, 1stT) and a separate group of 31 (3rd trimester, 3rdT) women [healthy or with CVR factors (obesity and/or hypertension and/or with gestational diabetes)] underwent echocardiography determination of left ventricular end-diastolic volume (LVEDV) and E/e' before (T0), immediately after (T1), and 15 min after (T2; SIC) AVO induced by passive leg elevation. Blood samples for NT-proBNP quantification were collected before and after the AVO. Acute leg elevation significantly increased inferior vena cava diameter and stroke volume from T0 to T1 in both 1stT and 3rdT, confirming AVO. LVEDV and E/e' also increased immediately after AVO (T1) in both 1stT and 3rdT. SIC adaptation (T2, 15 min after AVO) significantly decreased E/e' in both trimesters, with additional expansion of LVEDV only in the 1stT. NT-pro-BNP increased slightly after AVO but only in the 1stT. CVR factors, but not parity or age, significantly impacted SIC cardiac adaptation. A distinct functional response to SIC was observed between 1stT and 3rdT, which was influenced by CVR factors. The LV of 3rdT pregnant women was hypertrophied, showing a structural limitation to dilate with AVO, whereas the lower LV filling pressure values suggest increased diastolic compliance.NEW & NOTEWORTHY The sudden increase of volume overload triggers an acute myocardial stretch characterized by an immediate rise in contractility by the Frank-Starling mechanism, followed by a progressive increase known as the slow force response. The present study is the first to characterize echocardiographically the stretch-induced compliance (SIC) mechanism in the context of physiological hypertrophy induced by pregnancy. A distinct functional adaptation to SIC was observed between first and third trimesters, which was influenced by cardiovascular risk factors.

Hypertensive disorders of pregnancy and long-term cardiovascular health: FIGO Best Practice Advice

Hypertensive disorders of pregnancy (HDP) are the most common causes of maternal and perinatal morbidity and mortality. They are responsible for 16% of maternal deaths in high-income countries and approximately 25% in low- and middle-income countries. The impact of HDP can be lifelong as they are a recognized risk factor for future cardiovascular disease. During pregnancy, the cardiovascular system undergoes significant adaptive changes that ensure adequate uteroplacental blood flow and exchange of oxygen and nutrients to nurture and accommodate the developing fetus. Failure to achieve normal cardiovascular adaptation is associated with the development of HDP. Hemodynamic alterations in women with a history of HDP can persist for years and predispose to long-term cardiovascular morbidity and mortality. Therefore, pregnancy and the postpartum period are an opportunity to identify women with underlying, often unrecognized, cardiovascular risk factors. It is important to develop strategies with lifestyle and therapeutic interventions to reduce the risk of future cardiovascular disease in those who have a history of HDP.

Optimizing women's cardiovascular health after hypertensive disorders of pregnancy: a translational approach to cardiovascular disease prevention

Women who experience a hypertensive disorder of pregnancy (HDP) are amongst those at the highest risk of premature cardiovascular diseases (CVD). In Canada, effective CVD prevention interventions tailored specifically for this high-risk population are urgently needed. The objective of this review is to summarize a broad range of mechanistic and clinical studies examining the association of HDP with future CVD to inform postpartum clinical follow-up strategies focused on improving women's cardiovascular health. The current state of the science (animal model, observational and intervention studies) largely support two main hypotheses explaining the epidemiological link between HDP and long-term risk of CVD. First, that the complicated pregnancy "unmasks" women who were predisposed to CVD prior to pregnancy (i.e., women with subclinical atherosclerosis or pre-pregnancy CVD risk factors). Second, that HDP causes vascular dysfunction and/or worsens preexisting, subclinical CVD risk factors. Despite this strong evidence, several knowledge gaps remain in the understanding of specific mechanisms linking these two theories and the impacts of other important contributors (e.g., intersectional factors). From a clinical perspective, given the consistent data demonstrating a high prevalence of CVD risk factors after HDP, routine care after pregnancy at minimum should include: 1) standardized assessment of pregnancy-associated CV risks (P-CVRs); 2) early and regular screening of traditional CVD risk factors; 3) education and support for health behaviours as first line therapy (including breastfeeding); 4) individualized pharmacotherapy (i.e., statins, antihypertensives or antiglycemic agents as clinically indicated); and 5) consideration of a woman's health goals, reproductive plans and social context.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

There were persistent differences in vascular function parameters and brachial blood pressure throughout pregnancy in women with chronic hypertension who later developed adverse maternal or perinatal outcome. Further investigation into the possible clinical use of these findings is warranted. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

The influence of prenatal exercise and pre-eclampsia on maternal vascular function

During healthy pregnancy, the cardiovascular system undergoes diverse adaptations to support adequate transfer of oxygen and nutrients from mother to fetus. In order to accommodate the large expansion of blood volume and associated cardiac output, the structure, mechanics, and function of the arteries are altered. Specifically, in healthy pregnancy there is a remodeling of arteries (increased angiogenesis and vasodilation), a generalized reduction in arterial stiffness (increased compliance), and an enhanced endothelial function. The development of pregnancy complications, specifically pre-eclampsia, is associated with poor placentation (decreased angiogenesis), increased arterial stiffness, and vascular dysfunction (reduced endothelial function). Many of the positive adaptations that occur in healthy pregnancy are enhanced in response to chronic exercise. Specifically, placental angiogenesis and endothelial function have been shown to improve to a greater extent in women who are active during their pregnancy compared with those who are not. Prenatal exercise may be important in helping to reduce the risk of vascular dysfunction in pregnancy. However, our knowledge of the vascular adaptations resulting from maternal exercise is limited. This review highlights maternal vascular adaptations occurring during healthy pregnancy, and contrasts the vascular maladaptation associated with pre-eclampsia. Finally, we discuss the role of prenatal exercise on vascular function in the potential prevention of vascular complications associated with pre-eclampsia.

Bioimpedance cardiography in pregnancy: A longitudinal cohort study on hemodynamic pattern and outcome

Background

Pregnancy associated cardiovascular pathologies have a significant impact on outcome for mother and child. Bioimpedance cardiography may provide additional outcome-relevant information early in pregnancy and may also be used as a predictive instrument for pregnancy-associated diseases.

Methods

We performed a prospective longitudinal cohort trial in an outpatient setting and included 242 pregnant women. Cardiac output and concomitant hemodynamic data were recorded from 11^th–13^th week of gestation every 5^th week as well as at two occasions post partum employing bioimpedance cardiography.

Results

Cardiac output increased during pregnancy and peaked early in the third trimester. A higher heart rate and a decreased systemic vascular resistance were accountable for the observed changes. Women who had a pregnancy-associated disease during a previous pregnancy or developed hypertension or preeclampsia had a significantly increased cardiac output early in pregnancy. Furthermore, an effect of cardiac output on birthweight was found in healthy pregnancies and could be confirmed with multiple linear regression analysis.

Conclusions

Cardiovascular adaptation during pregnancy is characterized by distinct pattern described herein. These may be altered in women at risk for preeclampsia or reduced birthweigth. The assessment of cardiac parameters by bioimpedance cardiography could be performed at low costs without additional risks.

Serum Levels of Cardiac Markers NT-proANP and NT-proBNP in Brachycephalic bitches at Different Gestational Stages

The aim of this study was to determine serum levels of natriuretic peptide precursors (NT-proANP and NT-proBNP) during pregnancy in brachycephalic bitches. Fifteen healthy multiparous bitches were selected for this prospective study. Serum levels of NT-proANP and NT-proBNP were measured during anoestrous and at 14, 35, 42, 49 and 56 days (2nd, 5th, 6th, 7th and 8th weeks) of pregnancy. Fourteen animals had normal gestations, and one bitch developed single foetus syndrome. The natriuretic peptide levels of this animal were not included in this study; however, it is important to report that its NT-proANP levels were four times greater than those of normal patients. There was no significant difference (p = 0.072) in NT-proBNP levels between anoestrous (0.20 ± 0.10 ng/ml) and the different pregnancy weeks (0.27 ± 0.12 ng/ml). There was a positive correlation (p < 0.0001) between NT-proANP and gestational age, and the levels of this marker increased significantly (p < 0.0001) during the 6th (0.26 ± 0.06 ng/ml), 7th (0.28 ± 0.04 ng/ml) and 8th weeks (0.29 ± 0.05 ng/ml) when compared to anoestrous (0.18 ± 0.02 ng/ml). NT-proANP serum levels are correlated with gestational development and may be indicative of cardiovascular adaptation in canine brachycephalic pregnancy.

Noninvasive cardiac monitoring in pregnancy: impedance cardiography versus echocardiography

OBJECTIVE

The objective of this study was to report thoracic impedance cardiography (ICG) measurements and compare them with echocardiography (echo) measurements throughout pregnancy and in varied maternal positions.

METHOD

A prospective cohort study involving 28 healthy parturients was performed using ICG and echo at three time points and in two maternal positions. Pearson's correlations, Bland-Altman plots and paired t-tests were used for statistical analysis.

RESULT

Significant agreements between many but not all ICG and echo contractility, flow and resistance measurements were demonstrated. Differences in stroke volume (SV) due to maternal position were also detected by ICG in the antepartum (AP) period. Significant trends were observed by ICG for cardiac output and thoracic fluid content (TFC; P<0.025) with advancing pregnancy stages.

CONCLUSION

ICG and echo demonstrate significant correlations in some but not all measurements of cardiac function. ICG has the ability to detect small changes in SV associated with maternal position change. ICG measurements reflected maximal cardiac contractility in the a AP period yet reflected a decrease in contractility and an increase in TFC in the postpartum period.

Hypertension in pregnancy: a comprehensive update

Hypertensive disorders of pregnancies remain a central public health concern throughout the world, and are a major cause of maternal mortality in the developing world. Although treatment options have not significantly changed in recent years, insight on the pathogenesis of preeclampsia/eclampsia has been remarkable. With improved animal models of preeclampsia and large-scale human trials, we have embarked upon a new era where angiogenic biomarkers based on mechanism of disease can be designed to assist in early diagnosis and treatment. There is also a growing recognition of how elusive the diagnosis of eclampsia can be, especially in the postpartum period. Proper treatment of these patients depends heavily on the correct diagnosis, especially by the emergency physician. Finally, large epidemiologic studies have revealed that preeclampsia, once thought to be a self-limited entity, now appears to portend real damage to the cardiovascular and other organ systems in the long term. This review will present the latest update on our understanding of the various hypertensive disorders of pregnancies and their treatment options.