IntroductionCongenital heart defects (CHD) constitute second common cause of neonatal mortality despite general decrease of mortality rates during early life. Neonates with non-diagnosed prenatally CHDs, which were delivered at lower reference hospitals, have worse chances due to the lack of immediate specialist care. This is particularly important regarding hospitals with remote locations from cardiosurgery-cardiology centers. Prolonged hypoxia and metabolic acidosis during transportation are main causes of worse treatment outcomes in these cases. Prenatal diagnostics is extremely important. Diagnostic accuracy for detecting CHD at mid-gestation in experienced hands reaches 88,7 to 99,0%. Among late first-trimester ultrasound parameters related to CHD thickened nuchal translucency, abnormal ductus venosus (DV) flow, and tricuspid regurgitation should be considered. ObjectivesThe main aim of the study was the analysis of functional and structural cardiac abnormalities at the time of late first-trimester scan between 11 and 14 weeks. MethodsFrom first-trimester screening database records with known obstetric and neonatal outcomes were selected. Cases that demonstrated single pregnancies with fetal crown-rump length between 45 and 84mm were enrolled to these studies. Only subjects examined by one of two experienced examiners certified in first-trimester parameters and audited for more that 5 years by Fetal Medicine Foundation (FMF) were analyzed. The assessment of tricuspid and DV flow followed the FMF protocols. In study 1- 1075 cases were analyzed, in study 2- 5811, and in study 3- 1084. In study 1 (assessment of tricuspid flow) and in study 2 (evaluation of DV flow) the following parameters were analyzed: -maternal age in subgroups of euploidy and aneuploidy; ; -crown-rump length in subgroups of euploidy and aneuploidy;-frequency of primary and secondary markers of aneuploidy including cardiovascular ones (nuchal translucency, nasal ossification, tricuspid flow, DV flow, number of umbilical arteries) in subgroups of euploidy and aneuploidy;-coincidences of primary and secondary ultrasound markers of aneuploidy;-fetal heart rate in subgroups of euploidy and aneuploidy;-frequency of extracardiac and cardiac defects in subgroups of euploidy and aneuploidy;-sensitivity and specificity of tricuspid regurgitation (TR) and abnormal DV flow for detecting major aneuploidy and CHDs in euploidy.In the study 3 concerning first-trimester screening for CHD descriptive statistics was applied. Next sensitivity, specificity, positive and negative predictive values and diagnostic accuracy of screening methods based on four-chamber view and three-vessel and trachea view in color mapping were calculated. Basing on obtained results, patterns of the most common ultrasound pictures characteristic for particular CHDs were elaborated. ResultsTR was confirmed in 6.38% cases of euploidy. TR in aneuploidy was found 44%. The highest prevalence of TR was observed in fetuses with trisomy 18 (63.6%), next with trisomy 21 (44.4%), trisomy 13 (42.9%) and Turner syndrome (22.2%). All aneuploidies presenting TR showed additional markers of aneuploidy. Absence of DV (noDV) was depicted in 0.47% cases of euploidy. Reverse a-wave in DV flow (revDV) was observed in 2.46% of euploid fetuses. Fetuses with chromosomal aberrations showed noDV in 5.8% and revDV in 35.7%. noDV in aneuploidy was the most common in Turner syndrome (37.5%), next in trisomy 13 (7.14%), and trisomy 21 (1.19%). noDV profile was not observed in cases of trisomy 18. revDV in aneuploidy was the most common in trisomy 18 (47.8%), trisomy 13 (42.8%), trisomy 21 (33.3%) and Turner syndrome (25%). Mean NT values differed depending on the karyotype result between cases presenting various patterns of DV flow.Sensitivity of late first trimester four-chamber view (4CV) in color mapping for detecting CHD was 47,71% with specificity 100%. On the other hand sensitivity of three-vessel and trachea view (3VTV) reached 71,43% with specificity 100%. The most accurate results was obtained by applying combination of these two views –sensitivity of 88,57% and specificity of 100%. To compare NT above 3.5mm showed sensitivity of 37,14% with specificity of 95,61%. Lowering of NT cut-off to the 95th percentile caused the increase in sensitivity to 60% at the cost of lowering specificity to 89.51%. Basing on the most common ultrasound pictures of ventricular inflows 4 patterns were defined at the level of 4CV. At the level of 3VTV 6 patters were described.ConclusionsIsolated late first-trimester tricuspid regurgitation (TR) is a poor screening tool for detecting aneuploidy and CHDs in euploidy. TR in combination with other ultrasound markers of aneuploidy is the strongest predictor of chromosomal aberrations. Absent DV detected ; in coincidence with thickened nuchal translucency (NT) can be helpful in screening for Turner syndrome and differentiating this anomaly from other aneuploidies. Isolated reverse a-wave in DV flow (revDV) was found only in euploidy and trisomy 21. Any coincidence of revDV with other ultrasound markers of aneuploidy is a common feature of major trisomies. Isolated revDV is a poor screening tool for trisomy 21 and CHD in euploidy. Four-chamber view and three-vessel and trachea view in color mapping can be easily adopted in the routine first-trimester screening scan protocol. The combined application of these two cardiac views shows the most effective screening performance for CHD in the late first-trimester.