Peak Velocity Index For Veins Research Articles

Reference ranges for flow velocities and the indices of the ductus venosus in low-risk pregnancies

Objective:Ductus venosus blood flow velocity measurements are mandatory in many clinical indications. The evaluation of the flow is performed either by comparing results with general reference tables or by qualitative assessment of the “a” flow, in regard to reversed or absent flow in the spectral waveforms. The aim was to develop normal reference ranges in low-risk pregnancies in our population.Material and Methods:Measurements of flow velocities (S, v, D, a) and indices (pulsatility index for veins, peak velocity index for veins, a/S, S/a) were performed by a single experienced specialist in 1279 singleton, uncomplicated pregnancies between 11 and 40 weeks gestation. The absolute flow velocities (S, v, D, a, VmPeak) and indices were obtained from spectral waveforms using the equipment producer’s inbuilt system. The still images were stored in the picture archiving and communication system.Results:The predicted reference ranges of the ductus venosus blood flow velocities according to the gestational age are shown in tables and graphics. Predicted reference curves based on the 5th and 95th percentiles according to gestational week were plotted and are given in tables and figures.Conclusion:Normal reference ranges for absolute flow velocities and indices were calculated from a population of uncomplicated pregnancies attending a tertiary care center. The measurements were made from both the classic patterns of the waveforms and also considered variants of the spectral waveforms, which have recently been reported, for the first time in the medical literature.

REFERENCE RANGES FOR DOPPLER-ASSESSED FETAL PULMONARY VENOUS BLOOD FLOW VELOCITIES AND PULSATILITY INDICES IN NORMAL GROWTH FETUSES

Background: The aim of this study was to establish reference range with gestation for Doppler parameters in the fetal pulmonary venous blood of normal fetal growth, and indices reflecting left atrial pressure changes. Materials and Methods: Cross-sectional data were collected from 168 normal fetal growth between 28 and 40 weeks of gestation. Investigations of fetal pulmonary veins was performed by Doppler echocardiography to measure parameters: peak systolic velocity (S), peak diastolic velocity (D), end-diastolic velocity (A), and to calculate : peak velocity index for veins (PVIV), pulsatility index for viens (PIV). Regression analysis was used to detemine reference ranges with gestation. Results: Mean maternal age of study population was 29.79 ± 5.47 years old, and mean gestational age was 35.55 ± 2.73 weeks, average birth weight of fetus was 2547 ± 647 gr. A significant increase was observed in S, D, A with advancing gestation. Meanwhile, PVIV and PIV was decreasing significantly by advancing the gestational age. Conclusion: A reference range with gestation for Doppler parameters of fetal pulmonary venous blood of normal fetal growth has been established In the case of a normally growing fetus with a gestational age of 28 to 40 weeks, fetal pulmonary venous Doppler parameters are strongly correlated with gestational age. The flow velocity of the S, D, and A waves increases with gestational age. Peak velocity index (PVIV) and pulse index (PI) decrease with gestational age.

433 Maternal hyperoxia and its effect on the ductus venosus

The ductus venosus(DV) Doppler waveform is a valuable tool in the assessment of any fetal condition that may affect forward cardiac function. We sought to investigate the effects of maternal hyperoxygenation(MH) on the DV Doppler in the third trimester. Forty-six women with a singleton pregnancy ≥31 weeks’ gestational age(GA) were prospectively recruited.The DV Doppler was obtained at the isthmus, near its origin from the umbilical vein in a mid-sagittal view. A Doppler assessment of the umbilical artery (UA) was also performed. Doppler measurements were taken at baseline and following MH for 10minutes.Measurements of mean systolic, diastolic and ‘a’ wave velocities as well as pulsatility index for veins (PIV), preload index (PLI) and peak velocity index for veins (PVIV) ratios were obtained. Satisfactory DV Doppler recordings were obtained from 59% of participants.Qualitative assessment of the DV waveform confirmed a positive ‘a’ wave in all fetuses. DV mean systolic, diastolic and ‘a’ wave velocities increased following MH.The DV Doppler ratios including PIV, PLI and PVIV did not change in response to MH (Table 1).There were no changes in the resistance of the UA in response to MH. The DV responds to MH. Due to the increase in systole,diastole, and atrial contraction contemporaneously, the ratios between these elements were unchanged. As gestation advances the PIV and a-wave-related ratios decrease owing to a decrease in utero-placental resistance and an increase in cardiac compliance and contractility. We have demonstrated no change in the utero-placental resistance indices, therefore the most likely explanation is a constriction of the DV, suggesting that the DV is responsive to alterations in oxygen tension in the fetal blood.The decrease in the DV calibre in response to MH infers that the size of the DV is directly responsible for the shunting of umbilical venous blood away from the hepatic circulation.These findings warrant further investigation in relation to the effect of MH on myocardial function particularly in the context of congenital cardiac disease.

Can abnormal ductus venosus peak velocity index for veins in normal fetuses predict failure of functional closure of the foramen ovale in the postnatal period?

To investigate whether ductus venosus (DV) wave velocities and/or DV peak velocity index for veins (DV-PVIV) can predict failure of functional closure of the foramen ovale in the postnatal period. Fetal echocardiography was performed in 455 healthy women with uneventful pregnancies between the 20-24th gestational weeks. DV blood flow and DV-PVIV data were collected prospectively. Echocardiography was repeated in healthy subjects on the 30th postnatal day. Four hundred patients met the study criteria. Newborns with clearly visible foraminal flaps, interatrial septal defects smaller than 5 mm and right-to-left shunting through the defect were accepted as patent foramen ovale (PFO) (n=91). Newborns without PFO (n=309) comprised the control group. A statistically significant difference was detected between the groups with and without PFO in terms of mean DV-PVIV values, DV-D and DV-a wave velocities (p<0.05 for all). ROC analysis showed that increased DV-PVIV values were related to and predictive of PFO (AUC=0.75; p<0.001) and that a threshold value of 0.62, had a sensitivity of 86.8% (95% CI 78.1-93.0%) and a specificity of 51.7% (95% CI 46.1-57.5%). DV-PVIV values above 0.62 at the time of fetal echocardiographic examination can predict failure of functional closure of the foramen ovale in the postnatal period.

Effects of fetal cardiac anomalies on ductus venosus and aortic isthmus doppler profiles.

To demonstrate the blood flow profiles of fetuses with cardiac anomalies at the level of Ductus venosus (DV) and Aortic isthmus (AI) to evaluate the effects of fetal cardiac anomalies on these profiles, and how these profile changes contribute to cardiac anomaly screening studies as a marker. DV and AI doppler studies were applied to 64 singleton pregnant women with fetal cardiac anomalies and 74 pregnant women with healthy fetuses. DV-PVIV (peak velocity index for veins) for DV and IFI (isthmic flow index) for AI were used. DV doppler studies in fetuses with cardiac anomalies and healthy fetuses did not show statistically significant difference. But the results of the AI doppler studies had statistically significant difference in the fetal cardiac anomaly group with the exception of cases with dilatation and regurgitation. When right-sided heart anomaly and the remaining cases were compared with the control groups, AI doppler results also showed lower IFI values. DV doppler studies in the second or third trimester may not be suitable as a screening test for congenital heart disease, but AI doppler studies might be considered as a supporting parameter. But further studies are needed for routine clinical use.

A Reference for Ductus Venosus Blood Flow at 11-13+6 Weeks of Gestation

Objective: To establish reference ranges for ductus venosus (DV) blood flow assessment obtained transabdominally at 11-13⁺⁶ weeks of gestation. Methods: A cross-sectional study was conducted on singleton pregnancies with a crown-rump length (CRL) ranging from 45 to 84 mm, normal fetus, and subsequent newborn birth weight appropriate for gestational age. Measurements of DV Doppler variables were performed by experienced sonographers: peak velocity during ventricular systole (S-wave) and diastole (D-wave), nadir during atrial contraction (A-wave), time-averaged maximum velocity (TA_max), pulsatility index for veins (PIV), and peak velocity index for veins (PVIV). Results: A total of 304 fetuses were included. The mean CRL was 60.7 ± 7.2 mm (range: 45.9-75.5). The mean nuchal translucency measurement was 1.4 ± 0.4 mm. The S-wave, D-wave, A-wave, and TA_max values varied significantly with gestational age (p < 0.05) and regression models were constructed for each variable. The remaining variables, systolic/atrial wave ratio, preload index, PVIV, and PIV, did not vary significantly with gestational age within this CRL range. Conclusion: Reference ranges for DV Doppler assessment were established in normal fetuses. These ranges may be a useful tool for evaluation of anueploidy and fetal cardiac function.

Normal Reference Ranges of Ductus Venosus Doppler Indices in the Period from 14 to 40 Weeks’ Gestation

Objective: To construct reference ranges of ductus venosus (DV) Doppler indices in normal singleton pregnancies. Methods: A cross-sectional study was conducted on low-risk singleton pregnancies with accurate gestational age, and normal fetuses were enrolled into the study. Measurements of DV Doppler indices were determined by experienced sonographers. Poor quality images were excluded. Results: A total of 640 fetuses underwent DV measurements, ranging from 13 to 30 for each gestational week. The relationship between gestational age and DV Doppler indices was not linear. The best-fit regression equations are as follows: preload index = (5.061 – 0.4882) × exp (–0.211 × GA) + 0.4882; peak velocity index for veins = (7.498 – 0.5609) × exp (–0.2184 × GA) + 0.5609; pulsatility index for veins = (17.9 – 0.6053) × exp (–0.2512 × GA) + 0.6053; systolic/atrial wave ratio = (300 – 2.124) × exp (–0.3649 × GA) + 2.124. Notably, during the period from 14 to 20 weeks’ gestation, all of the four indices rapidly decreased and they were relatively stable or slightly decreased after that. The nomogram tables for various percentile ranges were constructed. Conclusion: A nomogram for DV Doppler indices for each gestational week during the period from 14 to 40 weeks’ gestation was established. These reference ranges may be a useful non-invasive tool for evaluation of fetal cardiac function.

Reproducibility of fetal ductus venosus blood flow velocity waveforms during first stage of labor

Fetal ductus venosus (DV) blood flow velocity waveforms are significantly altered during contractions in first stage of labor. We have evaluated the reproducibility of these waveforms during and between contractions. 90 women between 37th and 41st week of gestation were included in the study. The measurements of the DV were obtained by three different investigators during and between contractions. The pulsatility index for veins (PIV), peak velocity index for veins (PVIV), and fetal heart rate (FHR) were calculated offline. Furthermore, differences in PVIV (PVIVdiff) and PIV (PIVdiff) and a mean of FHR (FHRmean) were calculated. Statistical analysis was used to verify differences in the PIV, PVIV and FHR during and between contractions of each subgroup as well as for the PVIVdiff, PIVdiff and FHRmean between the subgroups. Investigator 1 examined 49 patients (group 1); investigator 2, 17 patients (group 2) and investigator 3, 24 patients (group 3), respectively. In all subgroups, there was a significant difference for the PVIV and PIV during and between contractions, but not for FHR. There was a correlation between gestational age and PVIVdiff, PIVdiff and FHRmean as well as for maternal age and PVIVdiff and PIVdiff. PVIVdiff and PIVdiff showed significant differences in group 1 compared to groups 2 and 3 (p<0.001), but not between groups 2 and 3. Significant differences in the measurements in the three subgroups have been revealed, which may be due to different timing of measurement during the contraction. For future studies further standardization of the measurement protocol should be established.

Ductus venosus velocimetry in monitoring pregnancy in women with pregestational diabetes mellitus

The purpose of this research was to assess the ability of ductus venosus (DV) Doppler velocimetry to predict adverse perinatal outcome in pregnancies complicated by pre-existing diabetes mellitus. This was a prospective study conducted at a tertiary referral obstetric facility in Brisbane, Australia. The study group included women with pregestational diabetes mellitus who delivered in the hospital between 1 January 1995 and 31 December 2006. The DV Doppler index was defined as abnormal if the DV peak velocity index for veins (PVIV) was equal to or greater than the 95(th) percentile for gestation. Adverse perinatal outcome included one or more of the following criteria: small-for-gestational-age infant; Cesarean section for non-reassuring fetal status; fetal acidemia at delivery; a 1-min Apgar score of <or= 3; a 5-min Apgar score of < 7; hypoxic ischemic encephalopathy; and stillbirth or neonatal death. The maternal characteristics and perinatal outcomes of pregnancies with normal or abnormal DV Doppler indices were compared. Eighty-two pregestational diabetic pregnancies were studied and an abnormal DV-PVIV was identified in 25 (30.5%). Adverse perinatal outcome was identified in eight of 25 (32.0%) pregnancies with an abnormal DV-PVIV compared to seven of 57 (12.3%) pregnancies with a normal DV-PVIV (P < 0.05). The sensitivity of the DV-PVIV in predicting adverse perinatal outcomes in pregestational diabetic pregnancies was 53.3%, the specificity was 74.6%, the positive predictive value was 32.0% and the negative predictive value was 87.7%. It may be useful to include DV-PVIV in the antenatal screening of pregnancies complicated by pregestational diabetes.

Prenatal diagnosis of tricuspid atresia: intrauterine course and outcome

To evaluate the intrauterine course and outcome of tricuspid atresia detected in the fetus. This was a retrospective review of all confirmed cases of tricuspid atresia detected prenatally between 1998 and 2006 in three tertiary referral centers in Germany. Fifty-four cases of tricuspid atresia were detected prenatally during the study period and confirmed postnatally: 28 (51.9%) cases had a concordant ventriculoarterial connection of which 14 also had pulmonary outflow obstruction; 25 (46.3%) cases had a discordant ventriculoarterial connection of which 14 also had aortic outflow obstruction, six had pulmonary outflow tract obstruction and two had other associated intracardiac anomalies; and one (1.9%) had a common arterial trunk. The peak velocity index for veins in the ductus venosus was significantly elevated in 19 of the 37 (51.4%) cases assessed; however, this finding did not correlate with adverse intrauterine outcome. There were associated extracardiac anomalies in 12 cases: five with chromosomal anomalies, two with VACTERL association, one with unilateral renal agenesis, one with hypospadia, one with hydrothorax, one with megacystis and one with agenesis of the ductus venosus. Seventeen of the 54 (31.5%) cases underwent termination of pregnancy, two (3.7%) died in utero, two (3.7%) died in infancy and 33 (61.1%) children survived with a median follow-up of 26 (range, 12-120) months. Prenatal echocardiography correctly anticipated the postnatal course and the need for neonatal intervention in 29/35 (82.9%) continued pregnancies; in the remaining six (17.1%) cases the right outflow tract obstruction had been underestimated. Tricuspid atresia and the frequently associated intracardiac anomalies can be diagnosed in the fetus with considerable accuracy. A thorough search for extracardiac malformations should be performed in order to rule out chromosomal anomalies and multiple malformation syndromes. Elevated pulsatility in the ductus venosus does not indicate cardiac failure. The short-term overall survival in continued pregnancies in our study exceeded 89%, with the greatest rate of loss being in the first year of postnatal life.

Non‐influence of fetal gender on ductus venosus Doppler flow in the first trimester

Recent findings have suggested that ductus venosus blood flow may be influenced by fetal gender. The aim of this study was to investigate further the influence of fetal gender on ductus venosus Doppler flow in the first trimester. This was a cross-sectional and retrospective study performed between January 1998 and January 2003. A total of 932 fetuses at between 10 and 14 weeks' gestation were included. The following inclusion criteria were used: singleton gestation; crown-rump length between 39 and 84 mm; and absence of fetal anomalies. The following variables of the ductus venosus were evaluated: peak velocity during ventricular systole (S-wave) and diastole (D-wave); nadir during atrial contraction in late diastole (A-wave); pulsatility index for veins (PIV); peak velocity index for veins (PVIV); and time-averaged maximum velocity (TAMXV). Four hundred and forty-eight (48.1%) female and 484 (51.9%) male fetuses were included in the study. Comparing males and females at between 10 and 14 weeks' gestation, there was no statistically significant difference in S-wave, D-wave, A-wave, PIV, PVIV or TAMXV. Our study suggests that fetal gender does not influence ductus venosus blood flow in the first trimester.

Venous Doppler ultrasound in 146 fetuses with congenital heart disease.

To assess the influence of isolated congenital heart disease (CHD) on fetal venous Doppler blood flow velocity waveforms. Doppler flow velocimetry was performed in the inferior vena cava and ductus venosus in 146 consecutive fetuses with antenatally diagnosed CHD. Gestational age ranged between 19 and 39 weeks. Fetuses with isolated CHD without non-immune hydrops fetalis (NIHF) (Group A, n = 89) were separated from seven fetuses showing isolated CHD with NIHF (Group B) and 50 cases complicated by chromosomal or other extracardiac malformations, intrauterine growth restriction or non-cardiogenic NIHF (Group C). The control group comprised 109 healthy fetuses of uncomplicated pregnancies. Individual peak velocity index for veins (PVIV) measurements were converted into their Z-scores (delta values) for statistical analysis. There was no statistical difference between fetuses with isolated CHD (Group A) and controls, for the delta PVIV of neither the ductus venosus nor the inferior vena cava. Statistical analysis revealed significant differences between non-isolated CHD fetuses (Group C) and controls for both vessels. However, in a separate analysis of isolated right heart malformations compared with the remaining isolated heart malformations (Groups A and B), a significant difference was observed for the ductus venosus, but not the inferior vena cava. There was an overall survival of 62%. In Group A, 58% of fetuses survived despite increased PVIV and 22% of fetuses with normal venous Doppler had an adverse outcome. All fetuses with cardiogenic NIHF (Group B) died. Doppler studies of the ductus venosus and inferior vena cava in fetuses with isolated CHD do not present sufficient alterations to be a reliable marker for screening purposes for CHD in mid-second- and third-trimester fetuses. Furthermore, venous Doppler did not predict fetal outcome in cases of isolated CHD. Abnormal venous Doppler results were mainly attributable to myocardial dysfunction and also to severe right heart obstruction even in the absence of congestive heart failure. Therefore, venous Doppler studies are clinically helpful in indirectly monitoring cardiac function in fetuses with cardiac malformations.

Correlação entre os índices dopplervelocimétricos da veia cava inferior e ducto venoso e a concentração de hemoglobina do cordão em fetos de gestantes isoimunizadas

OBJETIVO: o objetivo principal desse estudo foi verificar se existe correlação entre os índices dopplervelocimétricos da veia cava inferior e do ducto venoso e a concentração sérica da hemoglobina fetal. MÉTODOS: estudo transversal e prospectivo, realizado entre janeiro de 1998 e junho de 2001. Foram acompanhadas 31 gestantes isoimunizadas com resultado do teste de Coombs indireto maior que 1:8, que foram submetidas à pesquisa de hemólise fetal. Quando foram indicadas as transfusões intra-uterinas intravasculares, a hemoglobina do cordão foi dosada no início do procedimento. Nos demais casos, a hemoglobina do cordão foi mensurada no momento do parto, sempre por cesariana eletiva. Obteve-se um total de 74 procedimentos estudados, definidos como sendo cada transfusão intra-uterina precedida pela dopplervelocimetria venosa. A mensuração da concentração da hemoglobina fetal foi realizada no Hemocue® (B-Hemoglobin Photometer Hemocue AB; Angelholm, Sweden), dispositivo usado para a determinação quantitativa de hemoglobina no sangue. A dopplervelocimetria da cava inferior e do ducto venoso foi realizada antecedendo a coleta do sangue fetal, sempre em intervalo de tempo inferior a 24 horas. Os índices dopplervelocimétricos estudados foram o índice de pulsatilidade para veias (IPV), o índice do pico de velocidade para veias (IPVV) e a relação entre o pico de velocidade durante a fase de contração atrial e o pico de velocidade na sístole ventricular (relação CA/SV ou índice de pré-carga), na veia cava inferior, e o IPV, IPVV e a relação entre os picos de velocidade da sístole ventricular e da contração atrial (relação SV/CA), no ducto venoso. Foi realizado estudo de correlação entre a dopplervelocimetria da veia cava inferior e do ducto venoso e a hemoglobina do cordão, pela técnica de regressão linear simples. Realizou-se também estudo de associação entre os índices dopplervelocimétricos do compartimento venoso e a hemoglobina fetal inferior a 10 g/dL, por meio do teste do c². RESULTADOS: foi efetuado um total de 74 procedimentos. Em 23 desses a hemoglobina fetal era inferior a 7,0 g/dL. Houve correlação negativa significativa entre todos os índices dopplerfluxométricos estudados e a concentração de hemoglobina fetal (p<0,05), ou seja, os valores mais elevados dos índices dopplervelocimétricos foram observados nos fetos com anemia mais acentuada. Os fetos com nível de hemoglobina inferior ou igual a 10,0 g/dL apresentaram valores dos índices dopplervelocimétricos da cava e do ducto venoso acima do percentil 95 para a idade gestacional. CONCLUSÕES: a dopplervelocimetria da cava inferior e do ducto venoso pode ser utilizada como marcador não invasivo da anemia fetal grave.

Reference ranges for Doppler-assessed pulmonary venous blood flow velocities and pulsatility indices in normal human fetuses.

To establish reference ranges with gestation for Doppler parameters of fetal pulmonary venous blood flow during the second half of pregnancy, including not only peak velocities, but also relative indices reflecting left atrial pressure changes. In this cross-sectional study, 114 normal singleton pregnancies between 19 and 37 weeks' gestation were examined by Doppler echocardiography. In 98 fetuses, peak systolic velocity (S), peak diastolic velocity (D), end-diastolic velocity (A), and time velocity integral (TVI) were measured, and S/D ratio, pulsatility index for veins (PIV), as well as peak velocity index for veins (PVIV), were calculated. Regression analysis was used to determine reference ranges with gestation. With advancing gestation, a significant increase in S, D and A velocities as well as in TVI, was observed. Whereas the S/D ratio remained constant, PVIV and PIV decreased significantly during the second half of pregnancy. During the second half of pregnancy the increase in left atrial and ventricular compliance is reflected by the observed decrease in PIV and PVIV, which could be mainly due to the increased flow during atrial contraction. Such relative Doppler indices are better comparable than absolute values and are independent from the insonation angle. Potential clinical applications for such Doppler indices are conditions with possibly impaired left atrial function, like heart defects with left atrial obstruction or late stages of severe intrauterine growth retardation.

Normal values of fetal ductus venosus blood flow waveforms during the first stage of labor.

To present normal values of fetal ductus venosus blood flow waveforms during the first stage of labor during and between contractions. Seventy-eight women between the 37th and 41st weeks of gestation were included in the study. At distinct stages of cervical dilation, blood flow velocity waveforms of the fetal ductus venosus during and between contractions were visualized in fetuses with a normal non-stress test. The pulsatility index for veins, peak velocity index for veins and fetal heart rate were calculated off-line. The means +/- standard deviations (SD) during and between contractions were compared using the Wilcoxon test. Ductus venosus blood flow velocity waveforms were visualized during 331 contractions and 375 episodes of uterine quiescence in 74 of 78 fetuses (95%) during normal labor. The mean +/- standard deviation values of pulsatility and peak velocity indices for veins during contractions were 1.66 +/- 0.85 (median: 1.56, range: 0.29-4.69) and 1.46 +/- 0.65 (median: 1.34, range: 0.26-3.13), respectively. Between contractions the values were 0.48 +/- 0.19 (median: 0.46, range: 0.14-1.00) for the pulsatility index and 0.44 +/- 0.18 (median: 0.42, range: 0.14-1.00) for the peak velocity index for veins. These differences during and between contractions were highly significant (P-value < 0.0001), whereas the fetal heart rate showed no significant differences. There are significant differences in fetal ductus venosus blood flow waveforms during and between labor contractions. Further studies should evaluate whether these normal values of the fetal ductus venosus are beneficial for risk evaluation in fetuses with an abnormal non-stress test and/or intrauterine growth restriction.

P98Effects of maternal betamethasone administration on fetal Doppler flow velocity waveforms

BackgroundTo investigate the effect of maternal betamethasone administration on fetal arterial, venous and cardiac Doppler flow velocity waveforms.Method Patients: 13 women with singleton pregnancies considered at risk of preterm labour received an intravenous dosis of 2 × 8 mg betamethasone. Study design: Prospective study. Main outcome measures: Doppler studies were performed from the umbilical artery, middle cerebral artery, both uterine arteries, from the ductus venosus, inferior vena cava, right hepatic vein, form the av‐valves, right and left ventricular outflow tract and the ductus arteriosus before and after (30 min, 24, 48 and 72 h) betamethasone administration. Peak systolic velocities and maximum end‐diastolic velocities were recorded. Calculation of the resistance index (RI) for the arterial system, the peak velocity index for veins (PVIV) for the venous system and the E/A ratio for the av‐valves.ResultsNo significant variation was noted in the Doppler measurements before and after betamethasone administration. A slight and reversible increase of the peak systolic velocity of the ductus arteriosus and the right ventricular outflow tract was observed at 30 min after betamethasone administration.ConclusionBetamethasone administration does not cause a significant change of the arterial, venous and intracardiac Doppler flow velocity waveforms in healthy fetuses.

F125Fetal pulmonary venous Doppler flow velocity waveforms in congenital heart defects

Aim of the studyis to analyze blood flow velocity waveforms (FVW) in the pulmonary veins using pulsed Doppler ultrasound in fetuses with a prenatally detected congenital heart defect (CHD).MethodsIn 96 fetuses with various CHD Doppler FVW from the pulmonary veins were assessed. Gestational age varied between 18 and 38 weeks. Following Doppler parameters were analyzed and compared to reference ranges: systolic (S), diastolic (D) peak velocity, end‐diastolic velocity during atrial contraction (A), peak velocity index for veins (PVIV) and Pulsatility Index for veins (PIV).ResultsWe could distinguish 5 different patterns of FVW reflecting different stages of pulsatility and preload within the left atrium. Abnormal patterns were mainly observed in fetuses with left atrial obstruction and a restrictive foramen ovale having a reversed A‐wave as well as in mitral regurgitation.ConclusionsAbnormal FVW in fetal cardiac defects depend from the left atrial pressure rather than on the cardiac defect itself. Patterns of FVW can help in quick differentiation of increased interatrial pressure, which can impair early neonatal outcome.

Reference ranges for fetal venous and atrioventricular blood flow parameters.

This cross-sectional study establishes reference ranges with gestation for Doppler parameters of fetal venous and atrioventricular blood flow. Color flow Doppler was used to examine 143 normal singleton pregnancies at 20-40 weeks' gestation. Flow velocity waveforms were recorded from the ductus venosus, right hepatic vein and inferior vena cava. The waveforms are triphasic, reflecting ventricular systole, early diastole and atrial contraction. Peak velocities for these parameters were measured with pulsed Doppler and a new index, the peak velocity index for veins (PVIV), was calculated. Similarly, time-averaged maximum velocities for the whole cardiac cycle were measured and the pulsatility index for veins (PIV) was calculated. Flow velocity waveforms were also recorded at the level of the atrioventricular valves and the ratios of peak velocities at early diastolic filling (E) and atrial contraction (A) were calculated. Regression analysis was used to define the association of each measured and calculated Doppler parameter with gestational age. Blood flow velocities in the fetal veins and velocities and E/A ratios across the atrioventricular valves increased significantly with gestation, whereas PVIV and PIV decreased. Blood flow velocities were highest in the ductus venosus and lowest in the right hepatic vein, and PVIV and PIV were highest in the hepatic vein and lowest in the ductus venosus. In the ductus venosus, there was always forward flow throughout the heart cycle, whereas in the inferior vena cava and hepatic vein during atrial contraction, flow was away from or towards the heart or there was no flow. Pulsatility of flow velocity waveforms in the venous system is the consequence of changes in pressure difference between the venous system and the heart during the heart cycle. The finding that PVIV and PIV decrease with gestation is consistent with decreasing cardiac afterload and maturation of diastolic ventricular function.