Doppler echocardiographic evaluation of ventricular diastolic filling in fetuses with ductal constriction

Prenatal effects of maternal consumption of polyphenol-rich foods in late pregnancy upon fetal ductus arteriosus

Fetal circulation has characteristic features, being morphologically and functionally different from extrauterine circulation. The ductus arteriosus plays a fundamental role in directing the blood flow to fetal inferior body parts. Basically, the ductus arteriosus directs 80-85% of the right ventricular output arising from the superior vena cava, coronary sinus, and a small part from the inferior vena cava to descending aorta. Its histological structure is made up predominantly by a thick muscular layer, differently from the aorta and the pulmonary artery, which increases with gestational age. The fibers have a circumferential orientation, especially at the external layers, facilitating and making effective ductal constriction. These factors may generate lumen alterations which may cause fetal and neonatal complications, such as heart failure, hydrops, neonatal pulmonary hypertension, and even death. Classically, maternal administration of indomethacin and/or other antiinflammatory drugs interfere in prostaglandins metabolism, causing ductal constriction. However, many cases of fetal ductal constriction, as well as of persistent neonatal pulmonary artery hypertension, remain without an established etiology, being referred as "idiopathic." In recent years, a growing body of evidence has shown that herbs, fruits, nuts, and a wide diversity of substances commonly used in daily diets have definitive effects upon the metabolic pathway of inflammation, with consequent inhibition of prostaglandins synthesis. This antiinflammatory action, especially of polyphenols, when ingested during the third trimester of pregnancy, may influence the dynamics of fetal ductus arteriosus flow. The goal of this review is to present these new observations and findings, which may influence dietary orientation during pregnancy.

Pregnancy: Maternal and Fetal Heart Disease

Cardiac disorders complicate less than 1% of all pregnancies. Physiologic changes in pregnancy may mimic heart disease. In order to differentiate these adaptations from pathologic conditions, an in-depth knowledge of cardiovascular physiology is mandatory. A comprehensive history, physical examination, electrocardiogram, chest radiograph, and echocardiogram are sufficient in most cases to confirm the diagnosis. Care of women with cardiac disease begins with preconception counseling. Severe lesions should be taken care of prior to contemplating pregnancy. Management principles for pregnant women are similar to those for the non-pregnant state. A team approach comprised of a maternal fetal medicine specialist, cardiologist, neonatologist, and anesthesiologist is essential to assure optimal outcome for both the mother and the fetus. Although fetal heart disease complicates only a small percentage of pregnancies, congenital heart disease causes more neonatal morbidity and mortality than any other congenital malformation. Unfortunately, screening approaches for fetal heart disease continue to miss a large percentage of cases. This weakness in fetal screening has important clinical implications, because the prenatal detection and diagnosis of congenital heart disease may improve the outcome for many of these fetal patients. In fact, simply the detection of major heart disease prenatally can improve neonatal outcome by avoiding discharge to home of neonates with ductal-dependent congenital heart disease. Fortunately, recent advances in screening techniques, an increased ability to change the prenatal natural history of many forms of fetal heart disease, and an increasing recognition of the importance of a multidisciplinary, team approach to the management of pregnancies complicated with fetal heart disease, together promise to improve the outcome of the fetus with congenital heart disease.

Impact of selective laser ablation of placental anastomoses on the cardiovascular pathology of the recipient twin in severe twin-twin transfusion syndrome

OBJECTIVES

We investigated the impact of selective laser ablation on the cardiovascular pathology of the recipient twin in twin-twin transfusion syndrome.

STUDY DESIGN

Fetal echocardiograms and medical records were reviewed from 22 pregnancies with severe twin-twin transfusion syndrome where echocardiography was performed before and after laser.

RESULTS

Before laser, cardiomegaly associated with right and/or left ventricular hypertrophy without ventricular dilatation, was observed in most cases. Right ventricular and left ventricular systolic dysfunction (shortening fraction <28%) was present in 59% and 27%, respectively, and diastolic dysfunction (based on inflow and venous Dopplers) in 73%. Shortly after laser, biventricular systolic function improved significantly and diastolic function tended to improve (50%, P = .06). Functional pulmonary atresia, secondary to right ventricular systolic dysfunction, resolved in 2 of 2 cases at post-laser echocardiography. On serial assessment, diastolic function was normal in 7 of 10, hydrops regressed in 4 of 5, and neither progressive myocardial hypertrophy nor anatomical right ventricular outflow obstruction were found.

CONCLUSIONS

Selective laser ablation in severe twin-twin transfusion syndrome acutely improves biventricular systolic function and tends to improve diastolic function in the recipient twin.

Alternative parameters for echocardiographic assessment of fetal diastolic function

Alternative methods to assess ventricular diastolic function in the fetus are proposed. Fetal myocardial hypertrophy in maternal diabetes was used as a model of decreased left ventricular compliance (LVC), and fetal respiratory movements as a model of increased LVC. Comparison of three groups of fetuses showed that, in 10 fetuses of diabetic mothers (FDM) with septal hypertrophy (SH), the mean excursion index of the septum primum (EISP) (ratio between the linear excursion of the flap valve and the left atrial diameter) was 0.36 +/- 0.09, in 8 FDM without SH it was 0.51 +/- 0.09 (P=0.001), and in the 8 normal control fetuses (NCF) it was 0.49 +/- 0.12 (P=0.003). In another study, 28 fetuses in apnea had a mean EISP of 0.39 +/- 0.05 which increased to 0.57 +/- 0.07 during respiration (P<0.001). These two studies showed that the mobility of the septum primum was reduced when LVC was decreased and was increased when LVC was enhanced. Mean pulmonary vein pulsatility was higher in 14 FDM (1.83 +/- 1.21) than in 26 NCF (1.02 +/- 0.31; P=0.02). In the same fetuses, mean left atrial shortening was decreased (0.40 +/- 0.11) in relation to NCF (0.51 +/- 0.09; P=0.011). These results suggest that FDM may have a higher preload than normal controls, probably as a result of increased myocardial mass and LV hypertrophy. Prenatal assessment of LV diastolic function by fetal echocardiography should include analysis of septum primum mobility, pulmonary vein pulsatility, and left atrial shortening.

Behavior of septum primum mobility in third-trimester fetuses with myocardial hypertrophy

OBJECTIVES

The mobility of the septum primum (SP) in the fetus is a diastolic phenomenon and could be related to left atrial pressure. We studied the linear displacement of the SP in the left atrium in fetuses of diabetic mothers (FDM) with and without septal hypertrophy (SH) and in normal fetuses of normoglycemic mothers. In this study we set out to test the hypothesis that the linear displacement of the SP flap valve is less marked in fetuses with SH than in those without SH.

METHODS

The ratio between the linear displacement of the flap valve and the left atrial diameter (excursion index (EI)) was compared in ten FDM with SH, eight FDM with normal septal thickness and eight normal fetuses of non-diabetic mothers. Atrioventricular flow velocities were also compared in the three groups.

RESULTS

Comparison of the three groups showed that in FDM with SH, the mean EI was 0.36 +/- 0.09, in FDM without SH it was 0.51 +/- 0.09 (P = 0.001) and in the control fetuses it was 0.49 +/- 0.12 (P = 0.03). There was a significant negative correlation between septal thickness and EI in FDM with SH. There was no correlation between septal thickness and atrioventricular flow velocities.

CONCLUSION

Mobility of the SP in FDM with SH is reduced and there is an inverse correlation between the linear displacement of the SP and septal thickness. These findings may be related to changes in left ventricular diastolic function secondary to myocardial hypertrophy.

Evaluation of systolic and diastolic ventricular performance of the right ventricle in fetuses with ductal constriction using the Doppler Tei index

Fetal ductal constriction (DC) can depress right ventricular (RV) function. However, noninvasive assessment of fetal RV function remains difficult. We evaluated RV and left ventricular (LV) performance in fetuses with DC using the Doppler-derived Tei index. The Tei index measures the ratio of total time spent in isovolumic contraction and relaxation (isovolumic time) to the ejection time. Tricuspid inflow and RV outflow Doppler traces for the derivation of RV Tei indexes and mitral inflow and LV outflow traces for LV Tei indexes were measured in 78 fetuses of pregnant women who received indomethacin and 70 normal fetuses (gestational ages ranging from 20 to 39 weeks). DC occurred in 23 fetuses, defined as pulsatility index <1.9. In fetuses with DC, the RV isovolumic time was prolonged and RV ejection time was shortened, and the RV Tei index was high compared with those in fetuses that received indomethacin without DC and normal fetuses. Also, the RV Tei index clearly separated the fetuses with DC from normal and fetuses that received indomethacin without DC (0.74 +/- 0.14 vs 0.35 +/- 0.07 and 0.37 +/- 0.06, respectively; p <0.0001). The LV Tei index was not affected by DC. Serial study in 7 fetuses with DC showed that the RV Tei index decreased from 0.69 +/- 0.12 to 0.38 +/- 0.04 (p = 0.0002) after discontinuation of indomethacin coincident with ductal relaxation, although it remained elevated in 2 cases at the time of ductal relaxation. Thus, the Tei index is a useful and sensitive indicator for detecting abnormal RV performance in fetuses with DC.

Serial evaluation for myocardial performance in fetuses and neonates using a new Doppler index

BACKGROUND

Fetal echocardiography has been used for non-invasive evaluation of human fetal cardiac anatomy, function and hemodynamics. The Tei index, a new Doppler index known to be independent of both ventricular geometry and heart rate, has recently been applied to the evaluation of myocardial performance.

METHODS

In the present study, the Tei index was prospectively and longitudinally determined in 50 normal fetuses, 35 fetuses with intrauterine growth retardation (IUGR), 30 fetuses of diabetic mothers (DM) and 20 normal infants. The Tei index of both left and right ventricles was calculated from a Doppler ventricular inflow and outflow trace using the following formula: Tei index = (ICT + IRT)/ET, where ICT is isovolumetric contraction time; IRT, isovolumetric relaxation time; and ET, ejection time).

RESULTS

The Tei index of the left ventricle decreased linearly with advancing gestational age during 18-33 weeks and decreased acceleratively with increasing gestational age after 34 weeks. The index of the right ventricle decreased slightly and linearly with advancing gestational age during 18-41 weeks. In neonates, the Tci index of the left and right ventricle increased immediately and transitorily after birth and decreased and stabilized after 24 h of life. From 18 to 26 weeks of gestation, the Tei indices in fetuses with IUGR and of DM were not significantly different from controls. However, from 27 to 40 weeks of gestation, the Tei indices in both fetuses with IUGR and of DM were significantly greater than controls.

CONCLUSIONS

This gradual decrease in the Tei index during gestation may represent the maturational or developmental alternation of myocardial performance in utero. Fetuses with IUGR and of DM may have abnormal myocardial performance in later gestation.

Assessment of global left ventricular function in normal children and in children with dilated cardiomyopathy

A Doppler index combining systolic and diastolic time intervals (Tei index) has been reported to be useful for assessing global left ventricular (LV) function and predicting clinical outcome in adult patients with LV dysfunction. However, normal values in children and age-related changes in the index have not yet been clarified. The aim of this study was to prospectively determine normal values of the Tei index and the effect of aging on the index in children and to assess the global cardiac function in patients with dilated cardiomyopathy with this index. The subjects included 161 consecutive normal children aged 30 days to 18 years and 5 patients with dilated cardiomyopathy. The Tei index was defined as the sum of the isovolumetric contraction time and the isovolumetric relaxation time divided by the ejection time and was measured from conventional LV outflow and inflow Doppler velocity profiles. The Tei index correlated significantly with the logarithm of age (r = 0.51, P <. 001). The index decreased with aging until 3 years and then did not change after age 3 years. The Tei index in children under age 3 years (0.40 +/- 0.09, n = 80) was significantly higher than that in children ranging in age from 3 to 18 years old (0.33 +/- 0.02, n = 81). The index in patients with dilated cardiomyopathy (0.78 +/- 0. 28) was markedly increased compared with that in normal subjects. Age-related changes in the Tei index may reflect maturational or developmental alterations in the LV properties in infants. The data in this study give basic information for further quantitative assessment of global cardiac function in children with congenital or acquired heart disease.