Value of annular M-mode displacement vs tissue Doppler velocities to assess cardiac function in intrauterine growth restriction

Maternal obesity affects fetal myocardial function as early as in the first trimester

OBJECTIVE

To investigate cardiac function from 14 weeks' gestation in fetuses of obese pregnant women (FOW). Animal studies have shown that maternal obesity induces fibrosis in fetal myocardium. We hypothesized that fetal cardiac function would be impaired among FOW.

METHODS

A case-control study with longitudinal follow-up was performed at Trondheim University Hospital, Norway. In total, 80 pregnant women were included and the final population comprised 52 obese and 24 of normal weight (mean body mass index before pregnancy, 34.8 ± 4.1 vs 21.0 ± 2.2 kg/m(2) ; P < 0.001). The main outcome measures were global strain rate (GSR) and strain by tissue Doppler imaging, tissue Doppler velocities (TDVs) and interventricular septal thickness assessed by fetal echocardiography at gestational ages of 14, 20 and 32 weeks.

RESULTS

In FOW, fetal left ventricle (LV) and right ventricle (RV) GSR and strain were significantly lower than in fetuses of normal-weight pregnant women: LV GSR was 33.3% lower at 14 weeks, 22.4% lower at 20 weeks and 22.8% lower at 32 weeks of gestation (P < 0.001) with no difference in fetal heart rate. Systolic and late diastolic TDVs for LV were significantly lower from 20 weeks' gestation and remained lower throughout pregnancy. Fetal interventricular septum was 26.6% (P < 0.001) thicker in late pregnancy in FOW compared with normal-weight pregnancies.

CONCLUSIONS

At 14 weeks of gestation, we detected fetal myocardial dysfunction with reduced LV and RV GSR and strain in FOW compared with fetuses of women with normal weight. Our finding is alarming considering the high prevalence of obesity and may partly explain the predisposition of offspring to cardiovascular disease later in life.

Comparison of Two Different Ultrasound Systems for the Evaluation of Tissue Doppler Velocities in Fetuses

Introduction: Recent studies have reported variations of up to 30% between different ultrasound machines for tissue Doppler imaging (TDI), a problem that can significantly impact clinical diagnosis, patient management and research studies. The objective of this study was to assess repeatability and agreement between fetal myocardial peak velocities evaluated by TDI with two different ultrasound systems. Materials and Methods: Systolic (S'), early (E') and late (A') diastolic myocardial peak velocities at mitral and tricuspid annuli as well as at the basal septum were evaluated by spectral TDI in 150 fetuses using two different ultrasound systems: Siemens Antares (Siemens Medical Systems, Malvern, Pa., USA) and Vivid Q (General Electric Healthcare, Horten, Norway). A method comparison study was performed, calculating intraclass correlation coefficients (ICC), and agreement was assessed by Bland-Altman plots. Results: Annular peak velocities showed lower values when measured by Vivid Q compared to values measured by Siemens Antares. ICC ranged from 0.07 (septal S') to 0.33 (right A'), showing very poor repeatability for clinical application. Agreement between the two systems was also poor, with high coefficients of variation for all measurements. Conclusions: Fetal annular peak velocities obtained with different ultrasound systems are not directly comparable. This is consistent with previous data in adults and warrants the need of system-specific reference values, suggesting that the same ultrasound machine should be used for longitudinal follow-up.

Fetal cardiac function in late-onset intrauterine growth restriction vs small-for-gestational age, as defined by estimated fetal weight, cerebroplacental ratio and uterine artery Doppler

OBJECTIVE

Among late-onset small fetuses, a combination of estimated fetal weight (EFW), cerebroplacental ratio (CPR) and mean uterine artery (UtA) pulsatility index (PI) can predict a subgroup of fetuses with poor perinatal outcome; however, the association of these criteria with fetal cardiac structure and function is unknown. Our aim was to determine the presence and severity of signs indicating cardiac dysfunction in small fetuses, classified as intrauterine growth-restricted (IUGR) or small-for-gestational age (SGA), according to EFW, CPR and UtA-PI.

METHODS

A cohort of 209 late-onset small fetuses that were delivered > 34 weeks of gestation was divided in two categories: SGA (n = 59) if EFW was between the 3(rd) and 9(th) centiles with normal CPR and UtA-PI; and IUGR (n = 150) if EFW was < 3(rd) centile, or < 10(th) centile with a CPR < 5(th) centile and/or UtA-PI > 95(th) centile. The small population was compared with 150 appropriately grown fetuses (controls). Fetal cardiac morphometry and function were assessed by echocardiography using two-dimensional M-mode, conventional and tissue Doppler.

RESULTS

Compared with controls, both IUGR and SGA fetuses showed larger and more globular hearts (mean left sphericity index ± SD: controls, 1.8 ± 0.3; SGA, 1.5 ± 0.2; and IUGR, 1.6 ± 0.3; P < 0.01) and showed signs of systolic and diastolic dysfunction, including decreased tricuspid annular plane systolic excursion (mean ± SD: controls, 8.2 ± 1.1; SGA, 7.4 ± 1.2; and IUGR, 6.9 ± 1.1; P < 0.001) and increased left myocardial performance index (mean ± SD: controls, 0.45 ± 0.14; SGA, 0.51 ± 0.08; and IUGR, 0.57 ± 0.1; P < 0.001).

CONCLUSIONS

Despite a perinatal outcome comparable to that of normal fetuses, the population of so-defined SGA fetuses showed signs of prenatal cardiac dysfunction. This supports the concept that at least a proportion of them are not 'constitutionally small' and that further research is needed.

Longitudinal annular displacement by M-mode (MAPSE and TAPSE) in twin-to-twin transfusion syndrome before and after laser surgery

OBJECTIVE

To evaluate mitral and tricuspid annular plane systolic excursion (MAPSE and TAPSE) in fetuses with twin-to-twin transfusion syndrome (TTTS) before and after laser therapy.

METHODS

A prospective study in 24 fetal pairs with TTTS evaluated 24 h before and within 48 h after fetoscopy and 13 gestational age-matched normal monochorionic fetal pairs. MAPSE and TAPSE were measured in an apical or basal four-chamber view by placing the M-mode cursor at the lateral valve ring.

RESULTS

Mean preoperative MAPSE (controls 3.6 ± 1.3 mm vs. donors 2.7 ± 0.8 mm vs. recipients 2.8 mm ± 0.9; P < 0.001) and TAPSE (controls 4.4 ± 1.5 mm vs. donors 3.3 ± 1 mm vs. recipients 3.6  ± 1.1 mm; P < 0.001) values were significantly reduced in both TTTS fetuses. When subdividing according to TTTS stages, changes were significant in both stage I-II and III-IV subgroups, although differences were more pronounced in the latter. All observations remained unchanged 48 h post-fetoscopy.

CONCLUSION

Both recipient and donor fetuses had decreased global longitudinal motion, even in early TTTS stages.

Intermediate Diastolic Velocity as a Parameter of Cardiac Dysfunction in Growth-Restricted Fetuses

OBJECTIVE

To evaluate the intermediate intracardiac diastolic velocities in fetuses with growth restriction.

METHODS

Doppler waveforms of the two atrioventricular valves were obtained. Peak velocities of the E (early) and A (atrial) components, and the lowest intermediate velocity (IDV) between them, were measured in 400 normally grown and in 100 growth-restricted fetuses. The prevalence of abnormal IDV, E/IDV, and A/IDV ratios in fetuses presenting with perinatal death or acidemia at birth (pH ≤7.1) was estimated.

RESULTS

IDV was significantly lower and E/IDV ratios significantly higher in the two ventricles of growth-restricted fetuses with reduced diastolic velocities in the umbilical artery (p < 0.05). In 13 fetuses presenting with perinatal death or acidemia at birth, 11 (85%) had either an E/IDV or A/IDV ratio >95th percentile, whereas 5 (38%) showed absent or reversed atrial velocities in the ductus venosus (DV-ARAV; p < 0.04). Fetuses without DV-ARAV but with elevated E/IDV ratios in either ventricle were nearly 7-fold more likely to have perinatal demise or acidemia at birth (OR 6.9, 95% CI 1.4-34) than those with E/IDV ratios <95th percentile.

CONCLUSION

The E/IDV and A/IDV ratios in the two cardiac ventricles might provide information about the risk of perinatal demise or acidemia in growth-restricted fetuses.

A fetal cardiovascular score to predict infant hypertension and arterial remodeling in intrauterine growth restriction

OBJECTIVE

Intrauterine growth restricted (IUGR) fetuses experience cardiovascular remodeling that persists into infancy and has been related to cardiovascular outcomes in adulthood. Hypertension in infancy has been demonstrated to be a strong risk factor for later cardiovascular disease. Close monitoring together with dietary interventions have shown to improve cardiovascular health in hypertensive children; however, not all IUGR infants show increased blood pressure. We evaluated the potential of fetal echocardiography for predicting hypertension and arterial remodeling in 6-month-old IUGR infants.

STUDY DESIGN

One hundred consecutive IUGR and 100 control fetuses were observed into infancy. Fetal assessment included perinatal Doppler imaging, cardiac morphometry, ejection fraction, cardiac output, isovolumic relaxation time (IVRT), tricuspid annular-plane systolic excursion (TAPSE), and tissue Doppler imaging. Infant hypertension and arterial remodeling were defined as mean blood pressure of >95th percentile together with aortic intima-media thickness of >75th percentile at 6 months of age. Odds ratio were obtained for fetal parameters that were associated with infant outcomes.

RESULTS

Fetal TAPSE, right sphericity index, IVRT, and cerebroplacental ratio were the strongest predictors for postnatal vascular remodeling. A cardiovascular risk score that was based on fetal TAPSE, cerebroplacental ratio, right sphericity index, and IVRT was highly predictive of infant hypertension and arterial remodeling (area under the curve, 0.87; 95% confidence interval, 0.79-0.93; P < .001).

CONCLUSION

Fetal echocardiographic parameters identify a high-risk group within the IUGR fetuses who could be targeted for early screening of blood pressure and other cardiovascular risk factors and for promoting healthy diet and physical exercise.

Ultrasound assessment of fetal cardiac function

Introduction: Fetal heart evaluation with US is feasible and reproducible, although challenging due to the smallness of the heart, the high heart rate and limited access to the fetus. However, some cardiac parameters have already shown a strong correlation with outcomes and may soon be incorporated into clinical practice. Materials and Methods: Cardiac function assessment has proven utility in the differential diagnosis of cardiomyopathies or prediction of perinatal mortality in congenital heart disease. In addition, some cardiac parameters with high sensitivity such as MPI or annular peak velocities have shown promising results in monitoring and predicting outcome in intrauterine growth restriction or congenital diaphragmatic hernia. Conclusion: Cardiac function can be adequately evaluated in most fetuses when appropriate expertise, equipment and time are available. Fetal cardiac function assessment is a promising tool that may soon be incorporated into clinical practice to diagnose, monitor or predict outcome in some fetal conditions. Thus, more research is warranted to further define specific protocols for each fetal condition that may affect cardiac function.

Which intrauterine growth restricted fetuses at term benefit from early labour induction? A secondary analysis of the DIGITAT randomised trial

OBJECTIVE

The Disproportionate Intrauterine Growth Intervention Trial at Term (DIGITAT trial) showed that in women with suspected intrauterine growth restriction (IUGR) at term, there were no substantial outcome differences between induction of labour and expectant monitoring. The objective of the present analysis is to evaluate whether maternal or fetal markers could identify IUGR fetuses who would benefit from early labour induction.

STUDY DESIGN

The DIGITAT trial was a multicenter, parallel and open-label randomised controlled trial in women who had a singleton pregnancy beyond 36+0 weeks' gestation with suspected IUGR (n=650). Women had been randomly allocated to either labour induction or expectant monitoring. The primary outcome was a composite measure of adverse neonatal outcome, defined as neonatal death before hospital discharge, Apgar score <7, umbilical artery pH <7.05, or admission to neonatal intensive care. Using logistic regression modelling, we investigated associations between outcome and 17 markers, maternal characteristics and fetal sonographic and Doppler velocimetry measurements, all collected at study entry.

RESULTS

17 (5.3%) infants in the induction group had an adverse neonatal outcome compared to 20 (6.1%) in the expectant monitoring group. The only potentially informative marker for inducing labour was maternal pre-pregnancy body mass index (BMI). Otherwise, we observed at best weak associations between a benefit from labour induction and maternal age, ethnicity, smoking, parity, pregnancy-induced hypertension or preeclampsia, Bishop score and gestational age, or fetal sonographic markers (gender, estimated fetal weight, body measurements, oligohydramnios, or umbilical artery pulsatility index and end diastolic flow).

CONCLUSION

In late preterm and term pregnancies complicated by suspected intrauterine growth restriction, most of the known prognostic markers seem unlikely to be helpful in identifying women who could benefit from labour induction, except for maternal pre-pregnancy BMI.