False-Positive Rate in First-Trimester Screening Based on Ultrasound and Cell-Free DNA versus First-Trimester Combined Screening with Additional Ultrasound Markers.

OBJECTIVE: To determine whether screening for trisomy 21 based on first-trimester combined screening (FTCS) with assessment of nasal bone (NB), tricuspid flow (TCF), and ductus venosus flow (DVF) results in similar false-positive rates compared to ultrasound and cell-free DNA (cfDNA) screening. METHODS: This is a subanalysis of a prospective randomized controlled trial which was performed between October 2015 and December 2016. Pregnant women with a normal first-trimester ultrasound examination at 11 to 13 weeks' gestation were randomized into two groups: (1) FTCS with assessment of the NB, TCF, and DVF (extended FTCS [eFTCS]), and (2) ultrasound + cfDNA screening. The false-positive rate in screening for trisomy 21 was defined as the primary outcome parameter. RESULTS: The study population consisted of 688 women in each study arm. In the eFTCS group, the median delta fetal nuchal translucency thickness (NT) was 0.0 mm, free beta-hCG and PAPP-A were 0.96 and 1.11 MoM, and NB, TCF, and DVF PIV were abnormal in 0.9, 0.6, and 7.0% cases. In the ultrasound + cfDNA group, the median delta NT was 0.0 mm. In 10 pregnancies the cfDNA analysis was uninformative and the risk of trisomy 21 was based on eFTCS. There were no false-positive cases in the ultrasound + cfDNA group, whereas the false-positive rates were between 0.9 and 2.2% with eFTCS. CONCLUSION: Screening for trisomy 21 based on ultrasound + cfDNA has a lower false-positive rate than screening based on eFTCS.

Correlation of Parameters of Superior Vena Caval Flow with Transtricuspid Flow Pattern

BACKGROUND: Pulmonary venous flow velocity pattern (PVFVP) is widely used to assess LV diastolic function. It is known that the parameters of PVFVP have a significant correlation with the ratio of peak early diastolic filling velocity (E) to peak filling velocity at atrial contraciton (A) measured in the transmitral flow. However, the correlations between parameters of superior vena caval flow (SVCF) and transtricuspid E/A ratio have not been reported. Therefore the present investigation was performed to elucidate these correlations. METHODS: Fifty patients (26 men, mean age 63.1+/-11.1 years), who did not have significant tricuspid valvular disease and restrictive filling pattern on tricuspid and superior vena caval doppler, were included in this study. SVCF was recorded with the transducer positioned at subxiphoid area and the sample volume placed 2 cm within the superior vena cava. Blood flow across the tricuspid valve was obtained from standard four chamber view or modified parasternal four chamber view with the sample volume placed on leaflet tips. Recording was made during midexpiratory apnea. The following doppler parameters were measured: transtricuspid E and A velocity, E/A ratio: systolic (S) and diastolic (D) peak velocities and time velocity integrals (TVI), S/D velocity ratio, S/D TVI ratio, atrial reversal peak velocity (ArV) and TVI (ArTVI) in SVCF. RESULTS: 1) In SVCF, S velocity (63.7+/-11.8 cm/s vs 73.4+/-13.6 cm/sec, p1. And D TVI (7.1+/-3.0 cm vs 5.2+/-3.1 cm, p1. 2) As E/A ratio increased, diastolic TVI (r=0.315, p<0.05) and D/S TVI ratio (r=0.448, p<0.001) increased, and ArTVI (r=-0.376, p<0.01) and ArV (r=-0.416, p<0.01) decreased. 3) As E peak velocity increased, SVCF D peak velocity increased (r=0.305, p<0.05). CONCLUSIONS: Tricusupid E/A ratio has positive correlations with D TVI and D/S TVI ratio, and negative correlations with ArTVI and ArV. But there were no correlations in S velocity, D velocity, and S/D velocity ratio as the relation of mitral E/A ratio with PVFVP.