Objective: To evaluate the detection rate of congenital heart defect (CHD) during the first trimester screening for chromosomal abnormalities, the role of ultrasound soft markers including increased nuchal translucency (NT), tricuspid regurgitation (TR) and abnormal ductus venosus (DV) flow in the screening for cardiac anomalies was also investigated.
Methods: From January 2009 to January 2012, 4 673 fetuses were scanned at 11-14 weeks at Department of Fetal Medicine, the First Affiliated Hospital of Jinan University. The ultrasound findings and follow up outcomes were recorded, False-positive rate of different first-trimester ultrasound markers for the detection of CHD was calculated, sensitivity of the markers for all major CHD was calculated as well.
Results: There was a significant association between major CHD and first trimester ultrasound markers. (1) Overall findings:among the 4 673 fetuses, 31 fetuses were diagnosed CHD prenatally, 17, 12 and 2 of which were detected in the first, second and third trimester, respectively. In 22 of the 31 CHD cases, invasive procedure was performed, fetal karyotype was abnormal in 12 cases, including triosmy 21 (5 cases), trisomy 18 (2 cases), trisomy 13 (2 cases), Turner syndrome (2 cases) and pericentric inversion of chromosome 9 (1 cases). (2) NT measurement and prenatal detected CHD: in 4 673 cases, NT measurement between 95(th)-99(th) percentile were present in 206 (4.41%) , 5 cases were diagnosed CHD prenatally, in 4 of 5 cases were detected in first trimester; NT measurement <95(th) percentile were present in 4 430 (94.80%) , 16 cases were diagnosed CHD prenatally, in 5 of 16 cases were detected in first trimester; NT measurement>99(th) percentile (>3.5 mm) were present in 37 (0.79%, 37/4 673) , 10 cases were diagnosed CHD prenatally, in 8 of 10 cases were detected in first trimester. (3) TR and inverted a-wave at the DV and prenatal detected CHD: among 4 673 cases, TR or inverted a-wave at the DV were present in 51 (1.09%) , 98 (2.10%) respectively. TR was present in 8 of 31 CHD cases, inverted a-wave at the DV was present in 7 of 31 CHD cases. (4) Sensitivity of different first trimester ultrasound markers for detection of major CHD cases:in 31 CHD cases diagnosed prenatally, 23 cased were defined as major CHD. Sensitivity of at least one of the ultrasound markers, NT measurement between 95(th)-99(th) percentile, >99(th) percentile( >3.5 mm), TR or inverted a-wave at the DV for detection of major CHD cases was 74% (17/23), 22% (5/23), 39% (9/23), 35% (8/23), 30% (7/23) , respectively. (5) Specificity of different first trimester ultrasound markers for detection of CHD cases:specificity of NT measurement between 95(th)-99(th) percentile, >99(th) percentile (>3.5 mm), TR or inverted a-wave at the DV for detection of major CHD cases was 4.30% (201/4 673),0.58% (27/4 673),0.92% (43/4 673), 1.94% (91/4 673).
Conclusions: Routine first trimester soft markers for chromosomal abnormalities screening combined with cardiac assessment can detect quite a number of major heart defects. Increased NT, TR and abnormal DV flow can be important indicators for echocardiography, which is favorable to early prenatal diagnosis of CHD.