Carlos Geraldo Viana Murta

Application of Ductus venosus Doppler Velocimetry for the Detection of Fetal Aneuploidy in the First Trimester of Pregnancy

Objective: To test the hypothesis the application of ductus venosus Doppler velocimetry may serve as a screening tool between 10 and 14 weeks’ gestation for the detection of fetuses with chromosomal abnormalities. Methods: 372 consecutive fetuses were studied. Based on prior study, a chromosomal abnormality was suspected when either the nuchal translucency was above the 95th centile, or there was reversed or absent flow in the ductus venosus during atrial contraction. Sensitivity, specificity, and the negative and positive predictive values were calculated. Results: There were 29 chromosomally abnormal fetuses. Of these 29 fetuses, ductus venosus blood flow during atrial contraction was either absent (n = 2) or reversed (n = 25) in 93.1%. In the chromosomally normal fetuses (n = 343), only 6 (1.7%) had abnormal Doppler profiles in the ductus venosus (specificity = 98.3%, positive and negative predictive values = 81.8% and 99.4%, respectively). Conclusion: The Doppler waveform of the ductus venosus was at least equal to NT thickness measurement for the detection of chromosomal abnormalities.

O papel da translucência nucal no rastreamento de cardiopatias congênitas

OBJECTIVE Assess the accuracy of the nuchal translucency (NT) measurement between 11 and 13 weeks and 6 days of gestation as a sonographic marker to screen for congenital heart defects (CHD). METHODS This is a multi-center retrospective study in which singleton gestations of euploid fetuses were analyzed. NT measurement was performed in the first trimester examination when the fetal crown-rump length (CRL) was 45 to 84 mm, according to the criteria established by the Fetal Medicine Foundation. The cases were followed up to one month postpartum to assess the presence of CHD. RESULTS Three thousand six hundred and sixty four gestations were analyzed, of which twenty newborn infants had some congenital heart defect up to the first month of life (prevalence of 0.55%). The median NT in fetuses with CHD was 1.70 mm, and 1.60 mm in fetuses without CHD. However no statistically significant difference was observed between the two medians (Mann-Whitney test, p > 0.05). The NT sensitivity to detect CHD ranged from 15% to 20%, with a probability of false positive cases of 86.4% to 97.9%, depending on the cut-off point used. Odds ratio for CHD was high when compared to the classical indications for fetal echocardiography, ranging from 4.7 to 33.7, according to the cut-off point used. CONCLUSION Despite the low sensitivity of the test, increased NT is an important risk factor for CHD, and should be included in the strategy of prenatal screening for these diseases.

Reversed diastolic umbilical artery flow in the first trimester associated with chromosomal fetal abnormalities or cardiac defects

Abstract Background: Six cases have been reported of reversed end-diastolic umbilical artery (UA) blood flow at 10–14 weeks’ gestation. Four were associated with chromosomal anomalies, and one showed congenital heart disease. Cases: This report describes two cases of reversed end-diastolic UA flow at 10 and 12 weeks’ gestation with increased nuchal translucency in which cytogenetic analysis by chorionic villus sampling showed triploidy (69,XXX) and trisomy 9, respectively. In second case, the fetus had a ventricular septal defect. Conclusion: Reversed end-diastolic UA flow in the first trimester might be an important sign of chromosomal abnormalities in early pregnancy and might be a useful signal for the diagnosis of early cardiac defects.

Detection of Functional Changes of the Fetal Heart in the First Trimester of Gestation

The authors consider the possibility of using color Doppler of the ductus venosus and the measurement of nuchal translucency as a screening test for alterations in fetal cardiac functions in the first trimester of gestation. Review of the literature suggests that the combination of the ultrasonographic measurement of nuchal translucency and Doppler at 10 and 14 weeks of gestation can be effective in detecting certain cardiac abnormalities. This conclusion, however, is preliminary and needs to be further investigated.

Índices veno-arteriais para predição da acidemia fetal ao nascimento em gestações com insuficiência placentária

OBJECTIVE: to investigate whether it is possible to predict acidemia at birth in pregnancies with placental insufficiency using venous-arterial indices: pulsatility index for vein (PIV) of the ductus venosus (DV) over PI of the middle cerebral artery (MCA) and PIV of the DV over PI of the umbilical artery, and establish cut-off values for this prediction. PATIENTS AND METHODS: this was a prospective cross-sectional study involving forty-seven patients with placental insufficiency (umbilical artery resistance and pulsatility indices above the 95th percentile for gestational age) who were submitted to Dopplervelocimetry in the last 24 hours before delivery. All pregnancies were singleton, over 26 weeks of age and without structural or chromosome anomalies. Arterial cord blood was obtained for gasometry immediately after birth. Acidemia was defined as umbilical arterial pH < 7.20 in the absence of uterine contractions and pH < 7.15 in the presence of contractions. Metabolic or mixed acidemia at birth were considered pathological. A ROC curve was calculated for the venous-arterial indices: PIV DV/PI umbilical artery (UA) and PIV DV/PI MCA. A cut-off value was established and sensitivity, specificity, accuracy, positive and negative predictive values and positive and negative likelihood ratios were calculated. RESULTS: The DV/UA PI index was not a good predictor of acidemia at birth. The DV/MCA PI index was related to acidemia at birth (area under the curve 0,785, p = 0,004). The cut-off value was: 0,582, sensitivity 66,7%, specificity 77,1 and accuracy 74,5%. CONCLUSION: the PIV DV/PI MCA ratio is adequate for predicting acidemia at birth in pregnancies with placental insufficiency. The cut-off value was: 0,582.

Dopplervelocimetria no Rastreamento de Aneuploidias no Primeiro Trimestre da Gestação

Objective: to study the value of Doppler velocimetry of the ductus venosus and of the umbilical artery and vein, in the screening for chromosomal abnormalities at 10-14 weeks of gestation. Patients and Methods: a total of 314 fetuses were studied consecutively. In 112 cases a cytogenetic study was performed on material obtained from a biopsy of the chorionic villus, and in 202 cases the postnatal phenotype was used as a basis for the result. In addition to the routine ultrasonographic examination, all the fetuses were submitted to measurement of the nuchal translucency thickness and to Doppler velocimetry of the umbilical artery and vein, particularly of the ductus venosus. For statistical analysis the Fisher exact test and the Mann-Whitney test were used. Results: twenty-three cases of chromosomal abnormalities occurred. Of these abnormal cases, the ductus venosus blood flow during atrial contraction was absent (1 case) and reverse (22 cases), sensitivity was 92%. In the group of normal fetuses (289 cases), 6 evaluations demonstrated alterations in the Doppler of the ductus venosus (specificity of 97.6%, positive and negative predictive values of 76.7% and 93.3%, respectively); the false-positive rate was 2.4%. In reference to the umbilical vein and umbilical artery, there was no statistically significant difference between the abnormal and the normal group. Conclusion: The only parameter of Doppler velocimetry of the umbilical artery and vein which contributed to the detection of aneuploidies was the accidental discovery of the reverse blood flow in both vessels. Although our favorable results demonstrated that the Doppler velocimetry of the ductus venosus is effective in detecting aneuploidies, this conclusion, however, is preliminary and needs further investigation.

Venous-Arterial Doppler Ratios in the Prediction of Acidemia at Birth in Pregnancies with Placental Insufficiency

Objectives: Investigate the prediction of birth acidemia in pregnancies with placental insufficiency using two newly created venous-arterial Doppler ratios: pulsatility index (PI) of the ductus venosus (DV) over PI of the middle cerebral artery (MCA) and PI of the DV over PI of the umbilical artery and establish cut-off values for this prediction. Methods: This was a prospective cross-sectional study involving 47 patients with placental insufficiency managed in two Brazilian hospitals. All pregnancies were singleton, over 26 weeks of age and without structural or chromosome anomalies. A ROC curve was calculated for the venous-arterial ratios (independent variable) and acidemia (dependent variable). Results: The DV/AU PI ratio was not a good predictor of acidemia at birth. The DV/MCA PI ratio was related to fetal acidemia (area under the ROC curve 0.785, p = 0.004). The cut-off value was 0.582, sensibility 66.7%, specificity 77.1% and accuracy 74.5%. Conclusions: The DV/MCA PI ratio is adequate for the diagnosis of acidemia at birth in pregnancies with placental insufficiency. The cut-off value was 0.582.

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.

Ductus venosus versus cerebral transverse sinus Doppler velocimetry for predicting acidemia at birth in pregnancies complicated by placental insufficiency.

The objectives of this study is to compare ductus venosus (DV) and cerebral transverse sinus (CTS) Doppler velocimetry for predicting acidemia at birth in pregnancies complicated by placental insufficiency.

P01.03: Reproducibility of the fetal nasal bone length measurement

Objective: To determine the effect of first-trimester screening on the amniocentesis rate and the detection rate of fetal aneuploidy in a high risk population. Methods: We began to offer first-trimester screening (nuchal translucency, PAPP-A, and free beta HCG) to women at increased risk for fetal aneuploidy (mainly age 35 or older) in March 2002. We retrospectively reviewed the prenatal records of women who registered to deliver at Massachusetts General Hospital and who underwent a genetic amniocentesis during two time periods: prior to, and subsequent to, offering first-trimester screening. We also reviewed the cytogenetics database to identify all cases of fetal aneuploidy during the two time periods. Results: Data were collected over 13 months from each time period. The number of deliveries were similar (3174 and 3505 in calendar years 2000 and 2003, respectively) as were both the mean (30.1 and 31.0) and median (30.8 and 31.7) maternal age. There were 531 amniocenteses in the earlier period and 344 in the later period, a 35% decrease. Detection rate for fetal aneuploidy was 14/15 in the earlier period and 16/20 in the later period. The single undetected case in the earlier period was trisomy 21 in a 36 year-old woman who was not screened. In the later period there were 3 undetected cases trisomy 21, all to women who declined amniocentesis despite age > 35 and either increased risk on second-trimester serum screen (1 case) or abnormal findings on second-trimester ultrasound (2 cases). There was also a case of Turner’s syndrome in a 40 year-old woman who had a negative second-trimester serum screen. In the later period 5 cases of fetal aneuploidy were detected based on abnormal findings at first-trimester screening. Conclusions: The institution of first-trimester screening was associated with a 35% reduction in the amniocentesis rate without a demonstrable decrease in the detection rate of fetal aneuploidy.