Search

ABSTRACT Objective Recordings of blood flow velocity waveforms in the ductus venosus ( DV) and umbilical vein ( UV) are routinely used in order to predict fetal condition in high-risk pregnancies. The aim of this study was to investigate the relationship between pathological blood flow in the two vessels and perinatal outcome. Methods High-risk pregnancies ( n = 11 863) admitted from 1993 to 2011 for blood-flow examination, including recordings of DV pulsatility index for veins ( DV-PIV) and UV pulsations, were included. The results were related to perinatal outcome, using the last Doppler examination prior to delivery in the analysis. Results Abnormal DV-PIV was observed in 3.9% of cases, intra-abdominal UV pulsations in 1.3% and pulsations in the cord in 0.7%. As expected, the rate of UV pulsations increased with increasing DV-PIV Z-score. Fetuses with a pathological DV-PIV, but without UV pulsations, showed fewer signs of compromise. This was also true for cases with a DV-PIV ≥ 4 SDs above the mean (53.7% had steady flow in the UV). In contrast, the occurrence of UV pulsations seemed to be an indicator of fetal compromise, regardless of level of DV-PIV. Conclusions Abnormal fetal venous blood velocity is related to adverse outcome in high-risk pregnancies. However, abnormal DV-PIV is not a reliable indicator of fetal compromise unless UV pulsations are concurrently present, and should not be regarded an indication for emergency delivery. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

The article examines processes and methods for establishing reference curves for ductus venosus blood flow velocities during the first trimester compared with previously published curves. The results indicate a biphasic pattern in the reference range for pulsality index for veins (PUV) with an initial non-significant increase up to a crown-lump length of 63 millimeter and a fall thereafter.

The article focuses on a study in obstetrics that investigates the blood velocity pattern of the left portal vein and its development during the second half of pregnancy and tests the hypothesis that reversal of flow in the left portal vein may be a normal phenomenon. It notes that the left portal vein represents a watershed area in fetal circulation. It points out that the occurrence of pulsations in the left portal branch is a normal phenomenon, and so is reversal flow.

Objectives: Serial Doppler measurements of the ductus venosus are used increasingly for monitoring fetuses at risk of hemodynamic compromise, but existing reference ranges are based on cross-sectional studies and thus are less suitable for comparison with serial measurements. We aimed to establish longitudinal reference ranges for ductus venosus flow velocities and waveform indices and to provide the necessary terms for calculating conditional reference ranges for serial measurements. Methods: This was a longitudinal study of 160 low-risk pregnancies. Pulsed Doppler ultrasound was used to record ductus venosus blood flow velocities at 4-week intervals from 20-22 weeks of gestation onwards. Results: With a success rate of 93%, 547 measurements (four or five in each fetus) were used to establish reference ranges. The time-averaged maximum velocity was 50 cm/s at 21 weeks of gestation, increased to 60 cm/s at 32 weeks, and remained so until term. Similarly, the peak systolic velocity increased from 59 cm/s at 21 weeks to 71 cm/s at 31 weeks and remained so until term. The end-diastolic velocity showed a continuous increase from 31 cm/s at 21 weeks to 43 cm/s at 40 weeks. The pulsatility index for veins decreased from 0.57 at 21 weeks to 0.44 at 40 weeks. When conditioned by a previous measurement, the reference ranges for the next observation became narrower and commonly shifted compared with those of the entire population. Conclusion: The new longitudinal reference ranges presented here reflect the development of the ductus venosus flow velocities and velocity indices and are thus appropriate for serial measurements, particularly if conditional terms are included. [ABSTRACT FROM AUTHOR]

Objectives: The increased shunting of blood through the ductus venosus (DV) during stress situations is an important mechanism that ensures fetal survival. Although primate fetuses may serve to study the function of this important venous shunt, the rate of DV shunting has not been determined in non-human primates under normal conditions. Methods: DV shunting was measured in 11 marmoset (eight mothers) and eight singleton baboon fetuses in mid and late gestation using Doppler ultrasound. Results: DV shunting in marmosets was 39 +/- 20% (mean +/- SD) and 28 +/- 8% in baboon fetuses. Umbilical vein (UV) blood volume rate increased significantly in baboons with gestational age (GA) (UV flow volume = -111.8 + 1.6*GA; r = 0.94, P < 0.05) and slightly in marmosets (UV flow volume = -10.37 + 0.13*GA; r = 0.42, P > 0.05). Both UV diameter (r = 0.84) and the time-averaged mean UV flow velocity in baboons depended on GA (r = 0.8, P < 0.05). Distinct pulsation was found in marmoset fetuses in the UV (pulsatility index (PI) = 1.3 +/- 0.9) and the DV (PI = 1.9 +/- 1.2) with zero blood flow velocity during atrial contraction. Conclusions: A high level of pulsation is observed in the UV in marmoset fetuses. DV shunting in marmosets is higher than in baboon fetuses. [ABSTRACT FROM AUTHOR]

Objective No quantitative or qualitative Doppler velocimetry classification of vascular flow resistance covering all stages of forward and reversed flows exists. The objective of this study was to characterize uterine artery (UtA) flow velocity waveforms (FVWs) obtained during an oxytocin challenge test (OCT) and compare them to FVWs in spontaneous normal labor. Methods Uterine artery Doppler velocimetry was performed during and between uterine contractions in 61 high-risk pregnancies subjected to an OCT and in 20 normal pregnancies undergoing spontaneous labor. FVWs were classified relative to the presence of forward/absent/reversed flow during systole and diastole, and the time-averaged flow velocity over the heart cycle. Results Eleven different FVW classes were identified. No relationship between FVWs recorded during uterine inertia and contractions was found (P ≥ 0.2). In both groups, only forward FVWs were recorded between contractions, whereas during contractions flow reversal was more common in the OCT group (P < 0.002). In cases of predominantly reversed flow, a reciprocal relationship to FVW classes recorded in the contralateral artery was found. Conclusions UtA FVW patterns recorded during uterine contractions were not predicted by flow patterns recorded during uterine inertia. Reversal of flow direction was more common during oxytocin-induced uterine contractions than during spontaneous contractions. In cases of predominantly reversed flow, domains of the uterus may be supplied by blood from the contralateral UtA. These observations give new insights into the circulatory dynamics of the uterus during labor, and also point to a possible vasoconstrictory effect in the UtAs of oxytocin at high concentrations. [ABSTRACT FROM AUTHOR]

Objective To evaluate the effect of maternal isometric exercise on the placental blood flow as reflected by the velocimetric indices PI and RI derived from placental arteries. Subjects Thirty-four healthy women with normal singleton pregnancies between 22 and 35 weeks of gestation. Methods All subjects underwent an isometric handgrip exercise test. Maternal blood pressure and heart rate together with placental PI and RI were measured at rest, during the exercise and in the post-exercise recovery phase. All Doppler measurements were obtained using the Simultaneous Multigate Spectral Doppler Imaging (SM-SDI) technique, a new ultrasound modality that enables a Doppler study of multiple locations to take place within a very short time. Results There was a significant increase in the mean values of the maternal blood pressure and heart rate during the exercise and a significant decline in the recovery phase. There was no significant change in the mean values of the Doppler indices throughout the examination. Conclusion Isometric handgrip exercise test during pregnancy does not affect the impedance of the placental circulation. [ABSTRACT FROM AUTHOR]

The mean age was 62.0, and mean maximal diameter of tumour was 5.4 cm. At diagnosis, SMI revealed tumour blood flow clearly. After neoadjuvant chemotherapy, SMI detected decreased tumour blood flow in all patients. [Extracted from the article]

P08.10: Analysis of STIC flow imaging characteristics of fetal double aortic arch and right-side aortic arch with mirror carotid branch To improve the differential diagnosis of double aortic arch (DAA) and right-side aortic arch combined with mirror carotid artery branches (MRAA) by using 4-dimensional spatiotemoral image correlation (STIC) technology STIC blood flow assisted in diagnosing whether suspicious blood vessels converge into the descending aorta or not, and the origin, position and morphological characteristics of the LSA are also helpful for their differential diagnosis. [Extracted from the article]

Objectives Recent reports have suggested that nuchal translucency (NT) measurements in the first trimester may be influenced by fetal gender. Since both NT and central venous blood flow are considered to be related to fetal cardiac function, we investigated gender-related differences in first-trimester ductus venosus Doppler indices. Methods A total of 73 male and 79 female normal fetuses at 10-14 weeks of gestation were included in the study. The pulsatility index for veins (PIV), peak velocity during ventricular systole (S-wave), time-averaged maximum velocity (TAMV) and A-wave velocity (A-wave) were recorded in each case and converted to the corresponding Z-scores. Results The mean Z-score values of PIV, S-wave and TAMV were significantly lower in male fetuses compared to female fetuses (P < 0.01 for all three indices). By contrast, A-wave velocities were not different in the two groups. The correlation between S-wave velocity and TAMV was significant in both male (P < 0.001) and female (P < 0.001) fetuses, while PIV did not appear to be related to TAMV either in males (P = 0.90) or in females (P = 0.49). A-wave velocity had a significant negative correlation with PIV in both groups. Finally, PIV was significantly correlated with S-wave velocity in female fetuses (P < 0.01) but not in males (P = 0.14). Conclusion These findings suggest that early cardiovascular development may be different in male and female fetuses. [ABSTRACT FROM AUTHOR]