Fetal Tricuspid Regurgitation at the 11 + 0 to 13 + 6-Week Scan: Association With Chromosomal Defects and Reproducibility of the Method

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Tricuspid regurgitation (TR), diagnosed by pulsed-wave Doppler ultrasonography, is a common finding in aneuploid fetuses at 11 + 0 to 13 + 6 weeks gestation. A study performed by cardiologists found that early diagnosis of TR could be used to identify fetuses likely to have Down syndrome or other karyotypic abnormalities. This study attempted to determine how reproducible this diagnosis is and to compare the results obtained by experienced fetal cardiologists with those obtained by obstetricians trained in fetal echocardiography. Twelve obstetricians prospectively examined 1557 fetuses who were determined to be at increased risk of Down syndrome by first-trimester serum and nuchal translucency (NT) screening and both obstetricians and fetal cardiologists examined 128 fetuses, just before chorionic villus sampling. Criteria for inclusion in the study were a singleton pregnancy at 11 + 0 to 13 + 6 weeks gestation and a fetal crown-rump length (CRL) of 45 to 84 mm. All scans were done transabdominally. The median gestational age at the time of sonographic evaluation was 12 weeks. The tricuspid valve could be adequately examined in 1538 cases-nearly 99% of the total. TR was detected in 4.4% of 1323 chromosomally normal fetuses, 67.5% of 114 fetuses with trisomy 21, 33% of 42 with trisomy 18, and 15% of 59 with other chromosomal defects. Logistic regression analysis showed that delta NT (the difference between the observed and the expected NT measurements), but not CRL, significantly predicted the likelihood of TR in chromosomally normal fetuses. The likelihood ratio for trisomy 21 and trisomy 18 could be derived by dividing the likelihood of TR in trisomy 21 or 18 by the likelihood of TR in normal euploid fetuses. The obstetricians and the fetal cardiologists agreed in 88% of cases in which TR was present and 98% of those in which TR was not detected. The kappa coefficient of agreement was 0.872 (P <.0001). TR is commonly detected at 11 + 0 to 13 + 6 weeks gestation in fetuses with trisomy 21 and trisomy 18, and could be used to identify pregnancies whose risk of fetal aneuploidy justifies invasive diagnostic testing. Obstetricians trained in fetal echocardiography are able to reliably quantify tricuspid blood flow.