L. D. Allan

Challenges in the diagnosis of fetal non-chromosomal abnormalities at 11-13 weeks.

To examine the performance of the 11–13 weeks scan in detecting non‐chromosomal abnormalities.

Tricuspid regurgitation in the diagnosis of chromosomal anomalies in the fetus at 11–14 weeks of gestation

Objective: To analyse patient data to elucidate the apparent association between an abnormal karyotype and tricuspid regurgitation found during fetal echocardiography at early gestations. Setting: Tertiary referral centre for fetal medicine and cardiology. Methods: Fetuses between 11 and 14 weeks’ gestation were selected for detailed echocardiography. Referral reasons were increased nuchal translucency, a suspected cardiac or extracardiac malformation, and a family history of cardiac malformation. Intervention: The fetus was imaged transabdominally. The four chamber view, outflow tracts, arterial duct, and aortic arch were assessed on cross sectional imaging and colour flow mapping. Pulsed Doppler of the atrioventricular valves was recorded if possible. Subsequently, the fetal karyotype was ascertained by chorionic villous sampling. Results: Pulsed Doppler recording of the tricuspid valve was obtained for 262 fetuses. Tricuspid regurgitation was present in 70 (27%) of these, of whom 58 (83%) proved to have karyotype anomalies. In contrast, 68 (35%) of those without tricuspid regurgitation were found to have karyotype anomalies (95% confidence interval 36% to 59%, p < 0.001). Structural heart defects were detected in 34 of the 58 (59%) with tricuspid regurgitation and in 22 (32%) of those without. The chromosome defect most frequently found to be associated with tricuspid regurgitation was trisomy 21, but all types of karyotypic anomalies were seen in association. Conclusion: A careful search for tricuspid regurgitation is an important aspect of the evaluation of the early fetus, as this is frequently a marker for chromosomal defects even in the absence of structural heart disease.

Likelihood ratio for trisomy 21 in fetuses with tricuspid regurgitation at the 11 to 13 + 6-week scan

To determine the likelihood ratio for trisomy 21 in fetuses with tricuspid regurgitation at the 11 to 13 + 6‐week scan.

Relationship between nuchal translucency thickness and prevalence of major cardiac defects in fetuses with normal karyotype

To define the prevalence of major cardiac defects according to nuchal translucency (NT) thickness at the 11 to 13 + 6‐week scan in fetuses with normal karyotype.

The echocardiographic diagnosis of totally anomalous pulmonary venous connection in the fetus

BACKGROUND Infants with isolated totally anomalous pulmonary venous return often present severely decompensated, such that they are at high risk for surgical repair. On the other hand, if surgical repair can be safely accomplished, the outlook is usually good. Thus prenatal diagnosis would be expected to improve the prognosis for the affected child. OBJECTIVE To describe the features of isolated totally anomalous pulmonary venous drainage in the fetus. DESIGN Four fetuses with isolated totally anomalous pulmonary venous connection were identified and the echocardiographic images reviewed. Measurements of the atrial and ventricular chambers and both great arteries were made and compared with normal values. SETTING Referral centre for fetal echocardiography. RESULTS There were two cases of drainage to the coronary sinus, one to the right superior vena cava, and one to the inferior vena cava. Right heart dilatation relative to left heart structures was a feature of two cases early on, and became evident in some ratios late in pregnancy in the remaining two. CONCLUSIONS Ventricular and great arterial disproportion in the fetus can indicate a diagnosis of totally anomalous pulmonary venous connection above the diaphragm. However, in the presence of an atrial septal defect or with infradiaphragmatic drainage, right heart dilatation may not occur until late in pregnancy. The diagnosis of totally anomalous pulmonary venous drainage in fetal life can only be reliably excluded by direct examination of pulmonary venous blood flow entering the left atrium on colour or pulsed flow mapping.

Fetal tricuspid regurgitation at the 11 + 0 to 13 + 6-week scan: association with chromosomal defects and reproducibility of the method.

To determine the reproducibility of diagnosing tricuspid regurgitation (TR) at 11 + 0 to 13 + 6 weeks gestation, to examine further the relationship between TR and the presence of chromosomal defects and to calculate the likelihood ratios for trisomy 21 and trisomy 18 in fetuses with TR.

Right aortic arch in the fetus

To examine our experience of the detection of a right aortic arch in the fetus over an 8‐year period.

Doppler assessment of cardiac function at 11-14 weeks' gestation in fetuses with normal and increased nuchal translucency.

To investigate cardiac dysfunction as a potential underlying mechanism for increased nuchal translucency (NT) in fetuses with chromosomal abnormality or heart defects.

Fetal echocardiography at 11–13 weeks by transabdominal high-frequency ultrasound

To assess the accuracy of fetal echocardiography at 11–13 weeks performed by well‐trained obstetricians using a high‐frequency linear ultrasound transducer.

Contribution of ductus venosus Doppler in first-trimester screening for major cardiac defects.

Objective: To determine whether assessment of ductus venosus flow at 11–13 weeks’ gestation improves the detection rate of cardiac defects achieved by screening with nuchal translucency (NT) thickness. Methods: Prospective first-trimester screening for aneuploidies, including measurement of fetal NT and assessment of ductus venosus flow. The performance of different combinations of increased fetal NT and abnormal blood flow in the ductus venosus in screening for major cardiac defects was examined. Results: The study population of euploid fetuses included 85 cases with major cardiac defects and 40,905 with no cardiac defects. The fetal NT was above the 95th and above the 99th centile in 30 (35.3%) and 18 (21.2%) of the fetuses with cardiac defects, respectively, and in 1,956 (4.8%) and 290 (0.7%) of those without cardiac defects, respectively. Reversed a-wave was observed in 24 (28.2%) of the fetuses with cardiac defects and in 856 (2.1%) of those with no cardiac defects. Specialist fetal echocardiography for cases with NT above the 99th centile and those with reversed a-wave, irrespective of NT, would detect 38.8% of major cardiac defects at an overall false- positive rate of 2.7%. Conclusions: Assessment of ductus venosus flow improves the performance of NT screening for cardiac defects.