Screening for heart defects in the first trimester of pregnancy: food for thought

Sonographic Evaluation of Fetal Cardiac Anatomy in the Late First Trimester

Objective:

Congenital heart defects (CHDs) are the most common cause of infant death in the United States. Severe, complex cardiac anomalies make up approximately half of the cases and carry significant morbidity and mortality. The purpose of this literature review was to define a CHD screening protocol to be used in the first trimester.

Methods:

Literature was pulled that discussed the impact of color Doppler and spatiotemportal image correlation on image quality, explored the benefits and limitations of early screening, and analyzed the risk of bioeffects to the developing fetus.

Results:

A simplified cardiac screening protocol has been shown to be a feasible addition to the first trimester nuchal translucency scan.

Conclusion:

Color Doppler and three-dimensional sonography can be utilized during the first trimester to evaluate the fetal heart for major anomalies between 11 weeks and 13 weeks 6 days. Recommendations for future research and guidance from accrediting bodies are provided.

Screening performance of congenital heart defects in first trimester using simple cardiac scan, nuchal translucency, abnormal ductus venosus blood flow and tricuspid regurgitation

OBJECTIVE

The objective of this study was to analyze if the addition of simple cardiac scan in cases with increased nuchal translucency (NT) and/or abnormal ductus venosus (DV) blood flow, and/or tricuspid regurgitation (TCR) can improve detection of congenital heart defects (CHD) in chromosomally normal fetuses without non-cardiac defects at 11-13 + 6 gestational weeks in a population of singleton pregnancies.

METHODS

During the 10 years period, all singleton pregnancies at 11-13 + 6 weeks were routinely scanned for NT, DV blood flow and TCR assessment and, if a single of these parameters was abnormal, simple cardiac scan with 2D gray scale and color and/or directional power Doppler in 4-chamber (4-CV) and 3 vessel and trachea views (3VTV) was performed.

RESULTS

The sensitivity and specificity of NT ≥ 95th + DV R/A a-wave + TCR in detecting CHD were 77% and 97%, respectively, and of simple cardiac scan, 67% and 98%, respectively. Area under the curve of receiver operating characteristic curve of NT ≥ 95th + DV R/A a-wave + TCR was 0.838, and of NT ≥ 95th + DV R/A a-wave + TCR + simple cardiac scan was 0.915.

CONCLUSIONS

In chromosomally normal fetuses without non-cardiac anomalies, addition of simple cardiac scan to the combined first trimester screening parameters improves detection of major CHD during first trimester.

Does First-Trimester Screening Modify the Natural History of Congenital Heart Disease?

Background:

The study analyzed the impact of first-trimester screening on the spectrum of congenital heart defects (CHDs) later in pregnancy and on the outcome of fetuses and children born alive with a CHD.

Methods:

The spectrum of CHDs, associated comorbidities, and outcome of fetuses, either diagnosed with a CHD in the first trimester (Group I, 127 fetuses) or only in the second-trimester screening (Group II, 344 fetuses), were analyzed retrospectively between 2007 and 2013. Second-trimester fetuses diagnosed with a CHD between 2007 and 2013 were also compared with Group III (532 fetuses diagnosed with a CHD in the second trimester from 1996 to 2001, the period before first-trimester screening was introduced).

Results:

The spectrum of CHDs diagnosed in the first and second trimesters in the same time period differed significantly, with a greater number of comorbidities ( P <0.0001), CHDs with univentricular outcome ( P <0.0001), intrauterine deaths ( P =0.01), and terminations of pregnancy ( P <0.0001) in Group I compared with Group II. In Group III, significantly more cases of CHDs with univentricular outcome ( P <0.0001), intrauterine demise ( P =0.036), and early termination ( P <0.0001) were identified compared with fetuses diagnosed with CHDs in the second trimester between 2007 and 2013. The spectrum of CHDs seen in the second-trimester groups differed after first-trimester screening was implemented.

Conclusions:

First-trimester screening had a significant impact on the spectrum of CHDs and the outcomes of pregnancies with CHDs diagnosed in the second trimester. Early detection of severe forms of CHDs and significant comorbidities resulted in an increased pregnancy termination rate in the first trimester.

Prenatal detection of congenital heart defects at the 11- to 13-week scan using a simple color Doppler protocol including the 4-chamber and 3-vessel and trachea views

OBJECTIVES

The first goal of this study was to analyze the diagnostic performance of the 4-chamber view, 3-vessel and trachea view, and their combination in color mapping during early cardiac evaluations for selecting cases suspicious of congenital heart defects. The second goal was to describe the most common abnormal flow patterns at the levels of the 4-chamber and 3-vessel and trachea views in the late first trimester.

METHODS

We conducted a prospective observational study in which a simple cardiac sonographic protocol was applied in fetuses at gestational ages of 11 weeks to 13 weeks 6 days.

RESULTS

A total of 1084 patients with known postnatal or autopsy findings were included in the study. The median maternal age was 32.3 years (range, 27-40 years). The median crown-rump length was 62.2 mm (range, 45-84 mm). Overall, there were 35 cases with a confirmed congenital heart defect (3.22%), including 16 accompanied by aneuploidy. We found that our simple first-trimester cardiac protocol was an effective screening method for congenital heart defects. The most effective approach of the 3 evaluated by us was the combined application of the 4-chamber and 3-vessel and trachea views in color mapping compared to the 4-chamber and 3-vessel and trachea views alone. We defined the most common ventricular inflow patterns and the V sign. The technique we used was simple and easy to reproduce.

CONCLUSIONS

We confirmed that evaluation by two basic cardiac views allows for selection of most cases with a univentricular heart, atrioventricular septal defects, coarctation of the aorta, pulmonary stenosis, pulmonary atresia, and conotruncal defects.

Simplified first-trimester fetal cardiac screening (four chamber view and ventricular outflow tracts) in a low-risk population

OBJECTIVES

Our aim was to assess the accuracy of a simplified fetal cardiac study, inclusive of four-chamber view (4CV) and ventricular outflow tracts, performed during the 11-14 week screening by well-trained obstetricians to detect congenital heart diseases (CHDs).

METHODS

A transabdominal ultrasound was performed on 4820 singleton pregnant women at 11-14 weeks to visualize the visceral site, the 4CV, and the outflow tracts. Neonatal outcomes were recorded 6 and 12 months after birth.

RESULTS

Among the 4820 patients reviewed, 790 were excluded because of loss at prenatal or postnatal follow-up (649 cases), or inability to obtain adequate first-trimester sonographic cardiac evaluation (141 cases). Among the 4030 included cases, 32 CHD cases were detected (20 major and 12 minor); 18 of the major (90%) and five of the minor (42%) were detected or suspected in the first trimester, one major and six minor in the second trimester, and one major and one minor only after birth.

CONCLUSIONS

A simplified protocol is an effective tool to screen for CHD at 11-14 weeks.

Early fetal echocardiography and anomaly scan in fetuses with increased nuchal translucency

Nuchal translucency (NT) identified at the time of the 11-14 week scan has been established as one of the best tools for screening for Down syndrome. It has also proven to be of value in screening for other conditions such as cardiac defects and extra-cardiac structural abnormalities. In this article, we present data from our fetal medicine unit that highlight the importance of using NT measurement as a stratifying tool when referring for early scans. We propose that, whenever possible, in selected cases with increased NT, provision should be made for additional early scans at 14-18 weeks of gestation with a view to providing information on fetal structural integrity well ahead of the routine scheduled appointments. Early scans should incorporate detailed assessment of the fetal cardiac as well as extra-cardiac anatomy to diagnose or rule out major structural defects. This strategy will provide reassurance to a large number of prospective parents.

Learning curve and factors influencing the feasibility of performing fetal echocardiography at the time of the first-trimester scan

The purpose of this study was to assess the learning curve and factors influencing the feasibility of performing a complete fetal cardiac examination at the time of the first-trimester scan. The study included 103 fetuses undergoing first-trimester scans. The maternal body mass index, fetal crown-rump length, and 8 cardiac parameters were evaluated: 4-chamber view, tricuspid regurgitation, outflow tract crossover, bifurcating pulmonary artery, 3-vessel view, aortic arch, superior and inferior venae cavae on sagittal views, and Doppler images of the ductus venosus. All examinations were performed transabdominally by a single sonologist. The average times from the first to last cardiac images obtained were calculated. A complete examination was feasible in 55% of the cases: 15% of the first 52 and 94% of the last 51. Of the 8 cardiac parameters, 59.5% were seen in cases 1 to 21, 75.0% in cases 22 to 52, and 98.6% in the last 51 cases (P = .0001). The average times spent on the examinations increased from 4.37 to 9.3 minutes among the 3 groups (P = .032). There was no statistically significant influence for the crown-rump length (P = .899) or body mass index (P = .752). This study indicates that a fetal cardiac examination is feasible in the first trimester. Sonographer experience and the examination duration seem to be the most influential factors affecting the completeness of the examination.