L. C. França

Medida da Translucência Nucal no Rastreamento de Anomalias Cromossômicas

Purpose: to study the value of nuchal translucency (NT) measurement in the screening for chromosomal abnormalities at 10-14 weeks of gestation. Methods: a total of 1152 fetuses were studied consecutively. In 124 cases a cytogenetic study was performed on material obtained from a biopsy of the chorionic villus, and in 1028 cases the result was based on the postnatal phenotype. In addition to the routine ultrasonographic examination, all fetuses were submitted to measurement of the NT thickness. For statistical analysis Students t test and ANOVA were used. Sensitivity, specificity, positive and negative predictive values, false-positive rate and likelihood ratio were calculated. Results: twenty-three cases of chromosomal abnormalities occurred. Of these abnormal cases, NT measurement was above the 95th percentile in 16 (sensitivity of 69.5%). In the group of normal fetuses (1129 cases), NT measurement was above the 95th percentile in 41 (specificity of 96.3%, positive and negative predictive values of 28.0% and 99.3%, respectively, false-positive rate of 3.7% and likelihood ratio of 19.1). Conclusion: our results suggest that the presence of chromosomal abnormalities may be strongly suspected when there is an increased NT thickness. One can infer that the quantitative NT analysis is sufficient to classify the risk of chromosomal anomalies in the first trimester of the pregnancy. Although the ultrasound operators training and skill is still necessary, it is a method of clinical applicability.

Fluxo reverso no duto venoso: nova perspectiva na detecção de anomalias cromossômicas

Purpose: to evaluate the possible value of pulsed and color Doppler of ductus venosus blood flow in the screening for chromosomal abnormalities at 10-14 weeks of gestation. Methods: the ductus venosus flow velocity waveforms and the nuchal translucency (NT) thickness were obtained immediately before the chorionic villus sample in 26 pregnancies. We employed the following criteria for the suspicion of chromosomal defects: reverse or absent flow during atrial contraction and NT greater or equal to 3 mm. We calculated the sensitivity, the specificity, the negative and positive predictive value for each of the above items. Results: there were 9 chromosomal abnormalities (3 cases of trisomy 21, 2 cases of trisomy 13, 1 case of trisomy 9, 1 case of trisomy 22, 1 triploidy and 1 monosomy X). Abnormal ductus venosus flow was observed in all cases (sensitivity of 100%). In the normal fetuses (17 cases) only 1 had abnormal flow (specificity of 94%). Concerning NT, the sensitivity and the specificity were 88% and 76%, respectively. Conclusion: our preliminary results suggest that the presence of chromosomal abnormalities may be strongly suspected when an increased NT thickness is associated with an absent or reverse flow in the ductus venosus. We speculated that both methods are valid in the screening of chromosomal defects.

P25.01: The role of fetal nuchal translucency and ductus venosus Doppler at 11–14 weeks of gestation in the detection of Down syndrome

Objective: To determine whether Doppler velocimetry of the ductus venosus can improve the predictive capacity of increased nuchal translucency in the detection of trisomy 21 at 11–14 weeks of gestation. Methods: Ductus venosus Doppler ultrasound blood velocity waveforms were obtained prospectively at 11–14 weeks of gestation in 2280 consecutive singleton pregnancies. Waveforms were classified either as normal in the presence of a positive A-wave, or as abnormal if the A-wave was absent or negative. All cases were screened for chromosomal defects by a combination of maternal age and fetal nuchal translucency thickness. Concerm TN, a Down sindromy was suspected when the nuchal translucency was above the 95th centile. In 344 cases karyotyping was performed. Results: Down syndrome was found in 37 cases. On basis in the NT the overall detection rate, specificity, positive predictive value, negative predictive value and likelihood ratio for trisomy 21 were 85.7%, 97.1%, 99.9%, 28% and 44.9% respectively. On basis in the ductus venosus blood flow during atrial contraction the sensitivity, specificity, the negative and positive predictive values and likelihood ratio were 82.9%, 98.8%, 99.7%, 56.9%, 69% respectively. Conclusions: Enlarged nuchal translucency and abnormal ductus venosus blood flow are useful markers of trisomy 21 in the first trimester ultrasound screening, assessment of ductus venosus blood flow velocimetry could improve the predictive for the detection of Down syndrome.

P04.09: Why absent flow during the atrial contraction of the ductus venosus Doppler must be considered as a positive marker of Down syndrome?

Objectives: To determine whether absent flow during atrial contraction in the Doppler velocimetry of the ductus venosus can improve the predictive capacity of this method in the detection of Down syndrome at 11–14 weeks of gestation. Methods: Ductus venosus Doppler ultrasound blood velocity waveforms were obtained prospectively at 11–14 weeks of gestation in 2495 consecutive singleton pregnancies. In the first group waveforms were classified either as normal in the presence of a positive A-wave, or as abnormal if the A-wave was absent or negative. In the second group, waveforms were classified as abnormal if only A-wave was negative (reverse flow). All cases were screened for chromosomal defects by a combination of maternal age and fetal nuchal translucency thickness. Results: Down syndrome was found in 39 cases. In the first group the flow was abnormal in 30 cases, the overall detection rate, specificity, positive predictive value, negative predictive value and likelihood ratio for trissomy 21 were 76.9%, 99.0%, 54.5%, 99.6% and 75.5 respectively. On basis in the ductus venosus blood flow during atrial contraction as positive marker only A-wave was negative (24 cases) the sensitivity, specificity, the positive and negative predictive values and likelihood ratio were 61.5%, 99.1%, 53.3%, 99.4%, 71.9 respectively. Conclusions: Abnormal ductus venosus blood flow is an useful marker of Down syndrome in the first trimester ultrasound screening. We could improve the predictive for the detection of trisomy 21, and consequently becoming an excellent marker, by considering absent flow during atrial contraction as a positive marker (abnormal). Screening for Down syndrome in Brazil presents comparable results to those in other countries. It is a method of clinical applicability in any part of the world.

P17.14: Absent flow during the atrial contraction in the ductus venosus Doppler: normal or abnormal?

Objectives: The aim was evaluated the preliminary results of an implementation of assessment of risk in a tertiary center hospital in Brazil. Methods: This was a prospective study of 1.555 singleton pregnancies with a live fetus at 10–14 weeks of gestation attending for routine antenatal care in a tertiary hospital in Brazil. Fetal crown–rump length (CRL) and NT thickness were measured and the risks for trisomy 21 were calculated by a combination of maternal age and fetal NT according to the software provided by The Fetal Medicine Foundation. Results: The maternal age ranged from 13 to 48 years (median, 30 years, SD +7.6) whereas 15.5% were younger than 20 years (144/931), 32.0% and 7.4% older than 35 years (506/1555) and 40 years old. The body mass index was greater than 30 kg/m2 in 10% of these pregnant women and 61% from 18.5–24.9 kg/m2. Nulliparous and primiparous were found in 48.9% and 29.8% respectively. The distribution of NT measurements revealed that 64.5% and 11.6% of the population had measurements above the 50th and 95th percentile for gestational age with no difference among the six members of the group. The estimated risk was greater than 1 : 300 and 1 : 100 in 57 patients (3.7%) and in 16 patients (1.0%) respectively. Based on the distribution of maternal age, it was expected 2.6 cases of trisomy 21 and approximately the same number of other chromosomal defects. In this population, the invasive procedure was performed in 100 pregnant women and there were three cases of autosomal trisomies, one of trisomy of sex chromosomes, one case of Turner syndrome and two cases of structural chromosomal alterations. Of this population, 85.7% (6/7) had NT > 95th percentile for gestational age and 42.8% (4/7) were younger than 35 years old. Conclusions: The discriminative capacity of nuchal translucency measurement makes it a useful tool in screening for chromosomal abnormalities.

P31.11: Nuchal translucency and ductus venosus Doppler for trisomy 21 screening: which one is the best?

trisomy 21. In the remaining three cases with outcomes of trisomy 21, the diagnosis of trisomy 21 was not made in the first trimester although sonographic findings on the second-trimester ultrasound led to the prenatal diagnosis in two of the cases (atrioventricular canal in one and flat face with hypoplastic NB in the other). Conclusion: NB assessment can increase the detection rate of trisomy 21 by detecting the subset of trisomy 21 fetuses presenting with normal NT. Teaching and training in ultrasound assessment of the NB is important for establishing the real value of this ultrasound marker in the population of trisomy 21 fetuses with normal nuchal translucency thickness.

OP07.01: Aneuploidy screening on basis in the fetal ductus venosus blood flow at 11 to 14 weeks in a consecutive series of 1902 fetuses

Objectives: To evaluate the prognosis and outcome of persistent left superior vena cava (PLSVC) in fetus with congenital heart disease. Methods: Retrospective study of 11 cases of PLSVC detected prenatally between 2003 and 2006 in our center. Maternal fetal medicine specialists and pediatric cardiologists did the prenatal evaluation. Posnatal follow–up was obtained in all cases. All cases were presented to the Prenatal Diagnosis and Fetal Advanced Therapy Committee of Colsanitas Clinic. Results: Eleven cases with PLSVC were diagnosed. The diagnosis was made in the three vessel and trachea view when a supernumerary vessel to the left of the pulmonary trunk was identified, and in the 4-chamber view when two signs–a cyst at the lateral wall of the left atrium and dilated coronary sinus–were seen. In nine cases we found a structural anomaly in the heart: left ventricular hypoplastic syndrome (n = 2), double outlet right ventricle (DORV)(n = 2), conotruncal anomaly (n = 2), partial anomaly vein drainage (n = 1) and ventricular septal defect (VSD)(n = 2). In two cases PLSVC was an isolated finding. Of the VSD that were associated with PLSVC, one fetus had trisomy 13 and the other had hydrops. The fetus wuth DORV had a left isomerism syndrome. Of nine cases with PLSVC and a structural heart anomaly, seven fetuses died in perinatal period. 85% of these fetuses had anomalies in other systems and 75% were associated with complex heart disease. Conclusions: We believe that PLSVC associated with complex heart disease could be considered a marker of a poor prognosis. PLSVC could be a marker of congenital heart disease and is an indication for a detailed ultrasonographic and echocardiographic study.

P31.04: Nuchal translucency for aneuploidies: single center experience in Brazil

Introduction: First trimester screening for aneuploidy has been proposed as a major improvement because of higher detection rates and an earlier gestational age at diagnosis. Objectives: To evaluate the possible influence of first trimester examination on the time of diagnosis in cases with trisomy 21 in a referral center. Methods: Retrospective database analysis of all cases with trisomy 21 over a 4-year period (2003–2006). The studied population consisted of patients referred for targeted ultrasound examinations at different weeks, including patients with suspected or externally diagnosed aneuploidies. Results: A total of 160 fetuses with trisomy 21 were identified. Of those, 40 (25%), 37 (23.1%), 37 (23.1%) and 46 (28.8%) were diagnosed < 13 + 6 weeks, at 15 to 18 weeks, 19 to 22 weeks and > 22 weeks, respectively. Maternal age in the first three groups was significantly higher than in the group with late referral (37.1 vs. 34.9 years). In the first trimester, 38% of cases were diagnosed after screening in our center and 62% were referred for suspicious findings or confirmed trisomy 21. Second trimester diagnosis was 21.6% and 13.6% after screening, compared to 78.4% and 86.4% referred for suspected or diagnosed trisomy 21 at 15 to 18 weeks and 19 to 22 weeks, respectively. All cases with late referral had ultrasound abnormalities. Conclusion: Despite an increasing proportion of first trimester examinations performed at centers and by local obstetricians, the vast majority of cases with trisomy 21 are still diagnosed in the second trimester. Cases in the high risk population are detected earlier, as these patients receive targeted ultrasound examination in the first and early second trimester.

P02.09: Isolated placental aneuploidy associated with spontaneous resolution of hydrops fetalis

accuracy of prenatal diagnosis at our center is 73.2% (205/280). The four most accurate systems are abdominal wall (accuracy: 100%), hydrops fetalis (100%), thorax (100%), and gastrointestinal (82.2%) system. The four most inaccurate systems are heart (49%), musculoskeletal (66.7%), face and neck (70.8%), and neural axis (73.5%) system. The differences of accuracy in each system are statistically significant (p < 0.01). Conclusions: Our results show that the accuracy of ultrasound for detecting fetal anomaly differs according to fetal anatomical system. To improve the accuracy system oriented training program for fetal ultrasound is needed.

P01.42: Likelihood ratio for trisomy 21 in fetuses with abnormal nuchal translucency measurement at the 11–14‐week scan

Trisomy 9 in complete non-mosaic state is an uncommon chromosomal abnormality. Because of its high intrauterine lethality rate, mainly in the first trimester of pregnancy, only a few cases regarding sonographic findings have been reported. Ultrasound features leading to the diagnosis of this chromosomal abnormality include central nervous system, craniofacial, cardiovascular, genitourinary and musculoskeletal malformations as well as early intrauterine growth restriction and oligo-anhydramnios. We report two cases of complete trisomy 9 detected in the early second trimester. Both of them had a normal nuchal translucency (NT) at 11 week scan. In case 1, amniocentesis was performed because the risk for trisomy 18 at the combined test was greater than 1/50 (free BhCG: 0.09 MoMs; PaPP-A: 0.23 MoMs) and in case 2 because of advanced maternal age. Ultrasound examination before amniocentesis at 16 and 14 weeks of gestation, respectively, revealed similar findings (case 1: absent cerebellar vermis, ventriculomegaly, dysmorphic face and dysplastic kidneys; case 2: oligohydramnios, absent cerebellar vermis, hypotelorism, complete atrioventricular septal defect, echogenic bowel, echogenic kidneys, mild generalized subcutaneous edema and ductus venosus pulsatility index (DVPI) greater than 95th centile). Quantitative fluorescent polymerase chain reaction (QF-PCR) for chromosomes 21, 13, 18, X and Y was indicated with normal results in both of the cases but diagnosis of trisomy 9 was made by conventional cytogenetic analysis of amniotic fluid samples. An intrauterine fetal death was diagnosed in case 1; in case 2 parents opted for termination of pregnancy. Because the sonographic findings of trisomy 9 are similar to those of trisomy 18 and 13, in spite of its very rare incidence, diagnosis of trisomy 9 should be considered when QF-PCR studies are performed in these fetuses.