Assessment of the ductus venosus, tricuspid blood flow and the nasal bone in second‐trimester screening for trisomy 21

• Published in: Ultrasound in obstetrics & gynecology Vol. 37; no. 4; pp. 444 - 449
• Main Authors: Stressig, R., Kozlowski, P., Froehlich, S., Siegmann, H. J., Hammer, R., Blumenstock, G., Kagan, K. O.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01-04-2011; Wiley; Wiley Subscription Services, Inc
• Subjects: Adult; Age; Amniocentesis; Biological and medical sciences; Biomarkers - analysis; Bone blood flow; Cardiology. Vascular system; Chorionic Gonadotropin, beta Subunit, Human - analysis; Chromosome aberrations; Down Syndrome - diagnostic imaging; ductus venosus; Endocardial and cardiac valvular diseases; Female; Fetuses; Gynecology; Gynecology. Andrology. Obstetrics; Heart; Humans; Maternal Age; Medical genetics; Medical sciences; nasal bone; Nasal Bone - abnormalities; Nasal Bone - diagnostic imaging; Nasal Bone - embryology; Nuchal Translucency Measurement; Obstetrics; Population studies; Pregnancy; Pregnancy Trimester, Second; Pregnancy-Associated Plasma Protein-A - analysis; Regional Blood Flow - physiology; Regurgitation; Retrospective Studies; second trimester; tricuspid regurgitation; Tricuspid Valve Insufficiency - diagnostic imaging; Tricuspid Valve Insufficiency - physiopathology; Trisomy; trisomy 21; Ultrasonography, Prenatal; Ultrasound; Umbilical Veins - diagnostic imaging; Umbilical Veins - physiopathology; Vena Cava, Inferior - diagnostic imaging; Vena Cava, Inferior - physiopathology; Chromosomal aberration; Second trimester; Trisomy; Arantius canal; Gynecology; ductus venosus; trisomy 21; Aneuploidy; Cardiovascular disease; Down syndrome; Medical screening; Tricuspid regurgitation; Obstetrics; Blood flow; Pregnancy; Cardiac valvular disease; Nasal bone; Tricuspid valve
• ISSN: 0960-7692; 1469-0705; 1469-0705
• DOI: 10.1002/uog.7749

Objective
To examine the prevalence of reversed a‐wave in the ductus venosus, tricuspid regurgitation and absent nasal bone, in a second‐trimester population undergoing amniocentesis, after exclusion of major fetal defects and to estimate the performance in screening for trisomy 21 based on maternal age and these markers in a general population.
Methods
This was a retrospective study involving pregnancies undergoing amniocentesis due to increased risk for trisomy 21, mainly because of advanced maternal age. Before the invasive procedure, an ultrasound examination was carried out to exclude major fetal defects and to examine the ductus venosus, tricuspid blood flow and the presence of the fetal nasal bone. Modeling techniques were used based on 20 000 euploid pregnancies and 20 000 pregnancies with trisomy 21 to assess the screening performance in a general population.
Results
The study population consisted of 3613 euploid pregnancies and 35 cases with trisomy 21. In the euploid group, reversed flow in the ductus venosus, tricuspid regurgitation and an absent nasal bone was observed in 1.7%, 1.5% and 0.1% of cases, respectively. In the trisomic group, these markers were found in 14.3%, 11.4% and 14.3% of cases, respectively. For a 5% false‐positive rate, the detection rate in screening for trisomy 21, based on maternal age and either ductus venosus, tricuspid blood flow or nasal bone would be 33.8%, 32.4% or 31.4%, respectively. Screening by maternal age alone would detect 29.0% of the fetuses with trisomy 21. Receiver–operating characteristics curve analysis showed a slight but significant improvement in screening performance for trisomy 21 based on the inclusion of these markers.
Conclusion
Second‐trimester ultrasound screening for trisomy 21 based on maternal age with additional assessment of the ductus venosus, tricuspid blood flow and the fetal nasal bone in otherwise normal‐appearing fetuses is only marginally better than is screening by maternal age alone. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.