TBX2, a Novel Regulator of Labour.

Background and Objectives: Therapeutic interventions targeting molecular factors involved in the transition from uterine quiescence to overt labour are not substantially reducing the rate of spontaneous preterm labour. The identification of novel rational therapeutic targets are essential to prevent the most common cause of neonatal mortality. Based on our previous work showing that Tbx2 (T-Box transcription factor 2) is a putative upstream regulator preceding progesterone withdrawal in mouse myometrium, we now investigate the role of TBX2 in human myometrium. Materials and Methods: RNA microarray analysis of (A) preterm human myometrium samples and (B) myometrial cells overexpressing TBX2 in vitro, combined with subsequent analysis of the two publicly available datasets of (C) Chan et al. and (D) Sharp et al. The effect of TBX2 overexpression on cytokines/chemokines secreted to the myometrium cell culture medium were determined by Luminex assay. Results: Analysis shows that overexpression of TBX2 in myometrial cells results in downregulation of TNFα- and interferon signalling. This downregulation is consistent with the decreased expression of cytokines and chemokines of which a subset has been previously associated with the inflammatory pathways relevant for human labour. In contrast, CXCL5 (C-X-C motif chemokine ligand 5), CCL21 and IL-6 (Interleukin 6), previously reported in relation to parturition, do not seem to be under TBX2 control. The combined bioinformatical analysis of the four mRNA datasets identifies a subset of upstream regulators common to both preterm and term labour under control of TBX2. Surprisingly, TBX2 mRNA levels are increased in preterm contractile myometrium. Conclusions: We identified a subset of upstream regulators common to both preterm and term labour that are activated in labour and repressed by TBX2. The increased TBX2 mRNA expression in myometrium collected during a preterm caesarean section while in spontaneous preterm labour compared to tissue harvested during iatrogenic preterm delivery does not fit the bioinformatical model. We can only explain this by speculating that the in vivo activity of TBX2 in human myometrium depends not only on the TBX2 expression levels but also on levels of the accessory proteins necessary for TBX2 activity.

Doppler gradients, valve area and ventricular function in pregnant women with aortic or pulmonary valve disease: Left versus right.

OBJECTIVE: Little is known about the course of echocardiographic parameters used for the evaluation of valvular heart disease (VHD) during pregnancy, hampering interpretation of possible changes (physiological vs. pathophysiological). Therefore we studied the course of these parameters and ventricular function in pregnant women with aortic and pulmonary VHD. METHODS: The cohort comprised 66 pregnant women enrolled in the prospective ZAHARA studies or evaluated by an identical protocol who had pulmonary VHD or aortic VHD (stenosis/prosthetic valve). The control group comprised 46 healthy pregnant women. Echocardiography was performed preconception, during pregnancy and 1 year postpartum. Peak gradient, mean gradient, aortic valve area (AVA)/effective orifice area (EOA), left ventricular ejection fraction (LVEF) and right ventricular function (RVF; TAPSE) were assessed. RESULTS: Peak and mean gradients increased during pregnancy compared to preconception in women with aortic VHD and controls (p < 0.0125), but not in women with pulmonary VHD. AVA/EOA remained unchanged. Preconception and postpartum gradients were comparable in all groups. Mean LVEF was normal in pregnant women with VHD and controls. Mean TAPSE was lower (p < 0.001) in women with pulmonary VHD compared to women with aortic VHD and controls (<20 mm vs. ≥23 mm; p < 0.001). In women with pulmonary VHD a decrease of TAPSE was observed during pregnancy (p = 0.005). CONCLUSION: Physiological changes during pregnancy lead to increased Doppler gradients in women with aortic VHD. This increase was not found in women with pulmonary VHD, probably caused by impaired RVF. Therefore, evaluation of RVF during pregnancy might be important to prevent underestimation of the degree of stenosis.

Biological versus mechanical heart valve prosthesis during pregnancy in women with congenital heart disease.

BACKGROUND: We evaluate pregnancy outcome and anticoagulation regimes in women with mechanical and biological prosthetic heart valves (PHV) for congenital heart disease. METHODS: Retrospective multicenter cohort studying pregnancy outcomes in an existing cohort of patients with PHV. RESULTS: 52 women had 102 pregnancies of which 78 pregnancies (46 women) ≥20 weeks duration (59 biological, 19 mechanical PHV). Miscarriages (n = 19, ≤20 weeks) occurred more frequently in women using anticoagulation (P < .05). During 42% of pregnancies of women with mechanical PHV a combined low molecular weight heparin (LMWH) vitamin-K-antagonist anticoagulation regime was used (n = 8). Overall, cardiovascular, obstetric and fetal/neonatal complications occurred in 17% (n = 13), 68% (n = 42) and 42% (n = 27) of the pregnancies. Women with mechanical PHV had significantly higher cardiovascular (12% vs 32%, P < .05), obstetric (59% vs 85%, P = .02) and fetal/neonatal (34% vs 61%, P < .05) complication rates than women with biological PHV. This was related to PHV thrombosis (n = 3, P < .02), post-partum hemorrhage (P < .02), cesarean section (P < .02), low birth weight and small for gestational age (both P < .05). PHV thrombosis occurred in 3 pregnancies, including 2/5 pregnancies with pulmonary mechanical PHV. PHV thrombosis was related to necessary cessation of anticoagulation therapy or insufficient monitoring of LMWH. Other cardiovascular complications occurred equally frequent in both groups. CONCLUSION: Complications occur more often in pregnancies of women with a mechanical PHV than in women with a biological PHV, mainly caused by PHV thrombosis and bleeding complications. Meticulous monitoring of anticoagulation in pregnant women is necessary. Women with a pulmonary mechanical PHV are at high risk of complications.

Pregnancy in women with corrected aortic coarctation: Uteroplacental Doppler flow and pregnancy outcome.

OBJECTIVE: Women with repaired coarctation of the aorta (rCoA) are at risk of hypertensive disorders and other complications during pregnancy. Hypertensive disorders in pregnant women are associated with inadequate uteroplacental flow, which is related to adverse offspring outcome. The aim of this study was to investigate the relationship of maternal cardiac function, placental function and pregnancy complications in women with rCoA. METHODS: We included 49 pregnant women with rCoA and 69 controls from the prospective ZAHARA-studies (Zwangerschap bij Aangeboren HARtAfwijkingen, pregnancy in congenital heart disease). Clinical evaluation, echocardiography and uteroplacental Doppler flow (UDF) measurements were performed at 20 and 32weeks gestation. Univariable regression analysis was performed. RESULTS: Comparison of rCoA and healthy women. In women with rCoA, tricuspid annular plane systolic excursion (TAPSE) decreased during pregnancy (25.7mm to 22.8mm, P=0.006). UDF indices and pregnancy complication rates were similar in both groups. Offspring of rCoA women had lower birth weight (3233g versus 3578g, P=0.001), which was associated with ß-blocker use during pregnancy (ß=-418.0, P=0.01). Association of cardiac function and UDF. Right ventricular (RV) function before pregnancy (TAPSE) and at 20weeks gestation (TAPSE and RV fractional area change) were associated with impaired UDF indices (umbilical artery pulsatility index at 20weeks ß=-0.02, P=0.01, resistance index at 20 and 32weeks ß=-0.01, P=0.02 and ß=-0.02, P=0.01 and uterine artery pulsatility and resistance index at 20weeks gestation ß=-0.02, P=0.05 and ß=-0.01, P=0.02). CONCLUSIONS: Women with rCoA tolerate pregnancy well. However, RV function is altered and is associated with impaired placentation.

Cardiac adaption during pregnancy in women with congenital heart disease and healthy women.

OBJECTIVE: Pregnancy in women with congenital heart disease (CHD) is associated with deterioration in cardiac function. However, longitudinal data are scarce. This study describes serial changes in cardiac dimensions and function during pregnancy in women with CHD and compares these with healthy pregnant women (controls). METHODS: Eight tertiary centres prospectively enrolled 125 pregnant women with CHD (pregnancy duration <20 weeks). Controls (N=49) were recruited from low-risk midwife practices. Standardised echocardiography at 20 and 32 weeks gestation and 1 year postpartum was performed. RESULTS: Age and parity were comparable between both groups (p>0.1). Left ventricular ejection fraction (LVEF) <45% was present in 3.2% of women with CHD and 14.4% had tricuspid annular plane systolic excursion (TAPSE) <16 mm. Absolute values of ventricular function parameters and diameters were less favourable in women with CHD. No permanent changes occurred in right and left ventricular function parameters and dimensions in women with CHD. The patterns of change in cardiac function and dimensions were comparable between women with CHD and controls, except for LVEF (p=0.026). In women with right-sided CHD the pattern of TAPSE over time differed from controls (p=0.043) (no decrease in TAPSE postpregnancy in CHD). In women with left-sided CHD left ventricular end-diastolic diameter (LVEDD) tended to increase compared with controls (p=0.045). CONCLUSIONS: Absolute levels of ventricular function parameters and diameters differ between CHD and controls, but changes during and after pregnancy are generally comparable. However, different patterns over time seen for TAPSE and LVEDD in women with right-sided and left-sided CHD, respectively, compared with controls indicate the importance of echocardiographic follow-up during pregnancy in women with CHD.

Cardiac function and cardiac events 1-year postpartum in women with congenital heart disease.

BACKGROUND: Pregnancy is increasingly common in women with congenital heart disease (CHD), but little is known about long-term cardiovascular outcome after pregnancy in these patients. We studied the incidence of cardiovascular events 1-year postpartum and compared cardiac function prepregnancy and 1-year postpartum in women with CHD. METHODS: From our national, prospective multicenter cohort study, 172 women were studied. Follow-up with clinical evaluation and echocardiography and NT-proBNP measurement were performed during pregnancy and 12 months postpartum. Cardiovascular events were defined as need for an urgent invasive cardiovascular procedure, heart failure, arrhythmia, thromboembolic events, myocardial infarction, cardiac arrest, cardiac death, endocarditis, and aortic dissection. RESULTS: Cardiovascular events were observed after 11 pregnancies (6.4%). Women with cardiovascular events postpartum had significant higher NT-proBNP values at 20-week gestation (191 [137-288] vs 102.5 [57-167]; P = .049) and 1-year postpartum compared with women without cardiovascular events postpartum (306 [129-592] vs 105 [54-187] pg/mL; P = .014). Women with cardiovascular events during pregnancy were at higher risk for late cardiovascular events (HR 7.1; 95% CI 2.0-25.3; P = .003). In women with cardiovascular events during pregnancy, subpulmonary end-diastolic diameter had significantly increased 1-year postpartum (39.0 [36.0-48.0] to 44.0 [40.0-50.0]; P = .028). No other significant differences were found in cardiac function or size 1-year postpartum compared with preconception values. CONCLUSIONS: Cardiovascular events are relatively rare 1 year after pregnancy in women with CHD. Women with cardiovascular events during pregnancy are prone to develop cardiovascular events 1-year postpartum and have increased subpulmonary ventricular diameter compared with preconception values.

N-terminal pro-B-type natriuretic peptide predicts cardiovascular complications in pregnant women with congenital heart disease.

AIMS: In women with congenital heart disease (CHD), cardiovascular complications during pregnancy are common, but the risk assessment of these patients remains difficult. This study sought to determine the independent role of N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels in addition to other parameters in predicting adverse cardiovascular events during pregnancy in women with CHD. METHODS AND RESULTS: We conducted a national, prospective multicentre cohort study. Follow-up with clinical evaluation and echocardiography and NT-proBNP measurement was performed at 20-week gestation. Adverse cardiovascular events occurred in 10.3% of 213 pregnancies. N-terminal pro-B-type natriuretic peptide levels >128 pg/mL at 20-week gestation, the presence of a mechanical valve, and subpulmonary ventricular dysfunction before conception were independently associated with events [odds ratio (OR) 10.6 (P = 0.039), OR 12.0 (P = 0.016), and OR 4.2 (P = 0.041), respectively]. The negative predictive value of NT-proBNP levels <128 pg/mL was 96.9%. N-terminal pro-B-type natriuretic peptide levels >128 pg/mL at 20 weeks of gestation had an additional value in predicting the occurrence of adverse cardiovascular events on the top of the other identified predictors (area under the curve 0.90 vs. 0.78, P = 0.035). CONCLUSION: Increased NT-proBNP levels at 20 weeks of gestation are an independent risk predictor of cardiovascular events during pregnancy in women with CHD.

Uteroplacental blood flow, cardiac function, and pregnancy outcome in women with congenital heart disease.

BACKGROUND: Pregnant women with congenital heart disease (CHD) are susceptible to cardiovascular, obstetric, and offspring complications. In women with CHD, cardiac dysfunction may compromise uteroplacental flow and contribute to the increased incidence of obstetric and offspring events. METHODS AND RESULTS: We performed a prospective multicenter cohort study of pregnant women with CHD and healthy pregnant women. We compared clinical, laboratory, echocardiographic, and uteroplacental Doppler flow (UDF) parameters at 20 and 32 weeks gestation, and pregnancy outcome. We related cardiovascular parameters to UDF parameters and pregnancy outcome in women with CHD. We included 209 women with CHD and 70 healthy women. Cardiovascular parameters (N-terminal pro-B-type natriuretic peptide, left and right ventricular function) differed between both groups. UDF parameters were impaired in CHD women (umbilical artery pulsatility and resistance index at 32 weeks in CHD versus healthy women, P=0.0085 and P=0.017). The following cardiovascular parameters prepregnancy and at 20 weeks gestation were associated with UDF (umbilical artery resistance index) at 32 weeks at multivariable analysis: (1) right ventricular function (tricuspid annular plane systolic excursion) (P=0.002), (2) high N-terminal pro-B-type natriuretic peptide (P=0.085), (3) systemic (P=0.001), and (4) pulmonary (P=0.045) atrioventricular valve regurgitation. Women with CHD had more obstetric (58.9% versus 32.9%, P<0.0001) and offspring events (35.4% versus 18.6%, P=0.008) than healthy women. Impaired UDF was associated with adverse obstetric and offspring outcome. CONCLUSIONS: UDF parameters are abnormal in pregnant women with CHD. Cardiovascular function is associated with an abnormal pattern of UDF. Compromised UDF may be a key factor in the high incidence of offspring and obstetric complications in this population.