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Ferrazzi E, Lees C, Acharya G. The controversial role of the ductus venosus in hypoxic human fetuses. Acta Obstet Gynecol Scand 2019; 98:823-829. [PMID: 30742329 DOI: 10.1111/aogs.13572] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 02/04/2019] [Indexed: 12/25/2022]
Abstract
The ductus venosus plays a critical role in circulatory adaptation to hypoxia in fetal growth restriction but the mechanisms still remain controversial. Increased shunting of blood through the ductus venosus under hypoxic conditions has been shown in animal and human studies. The hemodynamic laws governing the accelerated flow in this vessel suggest that any dilation at its isthmus, which increases the blood flow shunting to the heart, is associated with a low, absent or reversed a-wave and a high pulsatility index. Cardiac dysfunction associated with increased atrial pressure as well as reduced ventricular compliance might be predominant mechanisms determining the profile of ductus venosus velocity waveforms in severe fetal growth restriction with signs of hypoxic compromise. Understanding the pathophysiology of the ductus venosus will underpin translation of the hypotheses developed through biostatistics toward explaining with more confidence Doppler changes in the fetal circulation in predicting clinical outcomes.
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Affiliation(s)
- Enrico Ferrazzi
- Department of Clinical and Community Sciences, University of Milan, Milan, Italy.,Department of Woman Child and Neonate, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Christoph Lees
- Center for Fetal Care, Queen Charlotte's and Chelsea Hospital, Imperial College Healthcare, National Health Service Trust, London, UK
| | - Ganesh Acharya
- Department of Clinical Science, Intervention and Technology, Karolinska Institute and Center for Fetal Medicine, Karolinska University Hospital, Stockholm, Sweden.,Women's Health and Perinatology Research Group, Department of Clinical Medicine, UiT-The Arctic University of Norway, Tromsø, Norway
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Leinan PR, Degroote J, Kiserud T, Skallerud B, Vierendeels J, Hellevik LR. Velocity profiles in the human ductus venosus: a numerical fluid structure interaction study. Biomech Model Mechanobiol 2013; 12:1019-35. [PMID: 23277410 DOI: 10.1007/s10237-012-0460-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 11/21/2012] [Indexed: 11/28/2022]
Abstract
The veins distributing oxygenated blood from the placenta to the fetal body have been given much attention in clinical Doppler velocimetry studies, in particular the ductus venosus. The ductus venosus is embedded in the left liver lobe and connects the intra-abdominal portion of the umbilical vein (IUV) directly to the inferior vena cava, such that oxygenated blood can bypass the liver and flow directly to the fetal heart. In the current work, we have developed a mathematical model to assist the clinical assessment of volumetric flow rate at the inlet of the ductus venosus. With a robust estimate of the velocity profile shape coefficient (VC), the volumetric flow rate may be estimated as the product of the time-averaged cross-sectional area, the time-averaged cross-sectional maximum velocity and the VC. The time average quantities may be obtained from Doppler ultrasound measurements, whereas the VC may be estimated from numerical simulations. The mathematical model employs a 3D fluid structure interaction model of the bifurcation formed by the IUV, the ductus venosus and the left portal vein. Furthermore, the amniotic portion of the umbilical vein, the right liver lobe and the inferior vena cava were incorporated as lumped model boundary conditions for the fluid structure interaction model. A hyperelastic material is used to model the structural response of the vessel walls, based on recently available experimental data for the human IUV and ductus venous. A parametric study was constructed to investigate the VC at the ductus venosus inlet, based on a reference case for a human fetus at 36 weeks of gestation. The VC was found to be [Formula: see text] (Mean [Formula: see text] SD of parametric case study), which confirms previous studies in the literature on the VC at the ductus venosus inlet. Additionally, CFD simulations with rigid walls were performed on a subsection of the parametric case study, and only minor changes in the predicted VCs were observed compared to the FSI cases. In conclusion, the presented mathematical model is a promising tool for the assessment of ductus venosus Doppler velocimetry.
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Affiliation(s)
- Paul R Leinan
- Biomechanics Division, Department of Structural Engineering, The Norwegian University of Science and Technology, 7491, Trondheim, Norway,
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Ebbing C, Rasmussen S, Kiserud T. Fetal hemodynamic development in macrosomic growth. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2011; 38:303-308. [PMID: 21557374 DOI: 10.1002/uog.9046] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
OBJECTIVE To determine the venous and arterial hemodynamics underlying macrosomic fetal growth. METHODS Fifty-eight healthy women who previously had given birth to a large neonate were included in a prospective longitudinal study. Of these, 29 gave birth to neonates with birth weight ≥ 90th percentile and were included in the statistical analysis. Umbilical vein blood flow and Doppler measurements of the ductus venosus, left portal vein and the hepatic, splenic, superior mesenteric, cerebral and umbilical arteries were repeated at 3-5 examinations during the second half of pregnancy and compared with the corresponding reference values. Ultrasound biometry was used to estimate fetal weight. RESULTS Umbilical blood flow increased faster in macrosomic fetuses, showed less blunting near term and was also significantly higher when normalized for estimated fetal weight (P < 0.0001). The portocaval perfusion pressure of the liver (expressed by the ductus venosus systolic blood velocity) and the left portal vein blood velocity (expressing umbilical venous distribution to the right liver lobe) were significantly higher. Systolic velocity was higher in the splenic, superior mesenteric, cerebral and umbilical arteries, while the pulsatility index was unaltered in the cerebral, hepatic, splenic and mesenteric arteries, but lower in the umbilical artery. CONCLUSIONS There is an augmented umbilical flow in macrosomic fetuses particularly near term, also when normalized for estimated fetal weight, providing increased liver perfusion, including the right liver lobe. Signs of increased vascular cross section and flow are also seen on the arterial side but not expressed in the pulsatility index of organs with prominent auto-regulation (i.e., brain, liver, spleen and gut).
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Affiliation(s)
- C Ebbing
- Department of Obstetrics and Gynecology, Haukeland University Hospital, Bergen, Norway and Department of Clinical Medicine, University of Bergen, Norway.
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Ebbing C, Rasmussen S, Godfrey KM, Hanson MA, Kiserud T. Fetal superior mesenteric artery: longitudinal reference ranges and evidence of regulatory link to portal liver circulation. Early Hum Dev 2009; 85:207-13. [PMID: 19013030 DOI: 10.1016/j.earlhumdev.2008.09.412] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 09/23/2008] [Accepted: 09/30/2008] [Indexed: 12/27/2022]
Abstract
OBJECTIVE To establish longitudinal reference ranges for the fetal superior mesenteric artery (SMA) flow velocity and pulsatility index (PI(SMA)). Also to examine the hemodynamic relationship to venous liver perfusion and umbilical flow distribution in the liver, to other splanchnic arteries, and more generally to the middle cerebral and umbilical artery. METHODS Prospective longitudinal study of 161 low-risk pregnancies using Doppler recordings including the SMA, repeated on 3-5 occasions at 3-5 weekly intervals. Umbilical venous flow was estimated, blood velocity in the shunt ductus venosus represented umbilico-caval (i.e. porto-caval) pressure gradient, and left portal vein blood velocity represented umbilical distribution within the liver. The correlation between PI(SMA) and the splenic and hepatic artery PI were analysed (PI(SA) and PI(HA)), and the association to middle cerebral and umbilical artery PI (PI(MCA) and PI(UA)) assessed. RESULTS Reference ranges for the SMA for gestational weeks 21-39 were based on 589 observations. Low impedance in the SMA (i.e. low PI(SMA)) was associated with low umbilical flow and porto-caval pressure gradient (i.e. <10th centile), and high distribution of umbilical flow to the right lobe (i.e. left portal vein blood velocity >90th centile). PI(SMA) correlated weakly with PI(SA) and PI(HA) (r=0.30, 95%CI 0.22-0.37, and r=0.39, 95%CI 0.27-0.51, respectively). PI(SMA) was positively associated with PI(MCA) and PI(UA). CONCLUSION We have provided longitudinal reference ranges for fetal SMA flow velocity and PI, and shown that the SMA, which perfuses the fetal gut, is also involved in the regulation of the liver perfusion.
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Affiliation(s)
- Cathrine Ebbing
- Department of Obsterics and Gynecology, Haukeland University Hospital, N-5021 Bergen, Norway.
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Ebbing C, Rasmussen S, Godfrey KM, Hanson MA, Kiserud T. Fetal celiac and splenic artery flow velocity and pulsatility index: longitudinal reference ranges and evidence for vasodilation at a low portocaval pressure gradient. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2008; 32:663-672. [PMID: 18816500 DOI: 10.1002/uog.6145] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
OBJECTIVES To establish longitudinal reference ranges for the fetal celiac and splenic arteries flow velocity and pulsatility index (PI), and to determine their hemodynamic relationship to venous liver perfusion and distribution and to other essential arteries. METHODS This was a prospective longitudinal study of 161 low-risk pregnancies. Doppler recordings of the celiac and splenic arteries were made on three to five occasions at 3-5-week intervals to establish reference ranges for blood velocity and PI measurements. Peak systolic velocity in the ductus venosus, a shunt between the umbilical and inferior caval veins, was used to represent the umbilicocaval (i.e. portocaval) pressure gradient, and the left portal vein blood velocity represented the umbilical distribution to the right liver lobe. The correlations between the celiac, splenic and hepatic arteries were determined, and their association with the middle cerebral and umbilical artery PIs (MCA-PI and UA-PI) was assessed. RESULTS Longitudinal reference ranges for the fetal celiac and splenic arteries were established based on 510 and 521 observations, respectively, during gestational weeks 21-39. Terms for calculating conditional reference ranges to be used for repeat observations are provided. Celiac and splenic artery PIs were low when portocaval pressure and umbilical supply to the right lobe were low (P < 0.0001). Their peak systolic velocity and PI were correlated (r = 0.7 (95% CI, 0.6-0.8) and r = 0.5 (95% CI, 0.3-0.6), respectively), while the PI of the hepatic artery correlated weakly with those of the celiac and splenic arteries. They were positively associated with the MCA-PI and UA-PI (P < 0.0001). CONCLUSION We provide longitudinal reference ranges for the fetal celiac and splenic arteries Doppler measurements and show that they are involved in maintaining portal liver perfusion independently from the hepatic artery.
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Affiliation(s)
- C Ebbing
- Department of Obstetrics and Gynecology, Haukeland University Hospital, Norway.
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Ebbing C, Rasmussen S, Godfrey KM, Hanson MA, Kiserud T. Hepatic artery hemodynamics suggest operation of a buffer response in the human fetus. Reprod Sci 2008; 15:166-78. [PMID: 18276952 DOI: 10.1177/1933719107310307] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
After birth, the hepatic artery buffer response helps to maintain liver perfusion. Here, the authors establish a Doppler technique to measure fetal hepatic artery flow velocity and test the hypothesis that the buffer response also operates prenatally. Women with low-risk pregnancies were recruited to a longitudinal study (N = 161). Measurement techniques and reference ranges for hepatic artery velocities and pulsatility index (PI) were established. Ductus venosus peak velocity (V(DVps)) represented the portocaval pressure gradient, and umbilical venous flow (Q(UV)) represented portal flow. Reference ranges were established for the more accessible left hepatic artery branch. Hepatic artery PI was lower in fetuses with V(DVps) <10th centile (P < .05) and in those with Q(UV) <10th centile ( P < .0001). Conversely, hepatic artery PI was higher in those with Q(UV) >90th centile (P < .0001). The authors establish a method for measuring fetal hepatic arterial blood velocity, provide reference ranges, and show that the hepatic artery buffer response operates prenatally.
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Affiliation(s)
- Cathrine Ebbing
- Department of Clinical Medicine, University of Bergen, Norway.
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Nii M, Hamilton RM, Fenwick L, Kingdom JCP, Roman KS, Jaeggi ET. Assessment of fetal atrioventricular time intervals by tissue Doppler and pulse Doppler echocardiography: normal values and correlation with fetal electrocardiography. Heart 2006; 92:1831-7. [PMID: 16775085 PMCID: PMC1861294 DOI: 10.1136/hrt.2006.093070] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVE To establish gestational age-specific reference values of normal fetal atrioventricular (AV) time interval by spectral tissue Doppler imaging (TDI) and pulse-wave Doppler (PD) methods, and to assess their correlation with signal-averaged fetal PR intervals (ECG). DESIGN Cohort study. SETTING Tertiary centre for fetal cardiology. PATIENTS AND MEASURES: 131 pregnant women between 14 and 42 weeks' gestation underwent 196 fetal echocardiograms and 158 fetal ECG studies. TDI-derived AV intervals were measured as the intervals from atrial contraction (Aa) to isovolumic contraction (IV) and from Aa to ventricular systole (Sa) at the right ventricular free wall. PD-derived AV intervals were measured from simultaneous left ventricular inflow/outflow (in/out) and superior vena cava/aorta (V/AO) recordings. RESULTS Measurements were possible by ECG in 61%, by TDI in 100%, by in/out in 100% and by V/AO in 97% of examinations. Aa-IV correlated significantly better with PR intervals (y = 0.67x + 38.29, R(2) = 0.15, p < 0.0001, mean bias 8.0 ms) than did in/out (R(2) = 0.10, p = 0.002, bias 18.7 ms) and V/AO (R(2) = 0.06, p = 0.02, bias 12.4 ms). Gestational age and AV intervals were positively correlated with all imaging modalities (R(2) = 0.19-0.31, p < 0.0001). CONCLUSION This study showed the feasibility of fetal AV interval measurements by TDI, and established gestational age-specific reference data. TDI-derived Aa-IV intervals track ECG PR intervals more closely than PD-derived AV intervals and thus should be used as the ultrasound method of choice in assessing fetal AV conduction.
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Affiliation(s)
- M Nii
- Division of Cardiology, The Hospital for Sick Children, Toronto, Ontario, Canada
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Abstract
PURPOSE OF REVIEW The purpose of this review is to highlight recent developments in the Doppler assessment of the fetal venous circulation with special reference to clinical applications in the human fetus. RECENT FINDINGS Doppler evaluation of the fetal venous circulation has increased our understanding of fetal cardiovascular function. Examples include the regulatory role of the ductus venosus in fetal nutrient partitioning and the significance of venous and arterial circulatory watershed areas. Alterations in cardiac afterload, contractility compliance, intravascular volume status and heart rate modulate venous and arterial flow velocity waveforms. Concurrent examination of these cardiovascular factors is of great importance in fetal growth restriction, complicated monochorionic multiple gestation, fetal hydrops and arrhythmia. In these conditions, comprehensive Doppler assessment provides critical diagnostic and prognostic information and has a key role in directing interventions. SUMMARY Venous Doppler has added a critical dimension to the understanding of fetal cardiovascular pathophysiology. In both health and disease, venous Doppler must now occupy a fundamental position in the comprehensive assessment of the fetal circulation.
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Affiliation(s)
- Ahmet Alexander Baschat
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland, Baltimore, Maryland 21201, USA.
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Tchirikov M, Schlabritz-Loutsevitch N, Nathanielsz PW, Beindorff N, Schröder HJ. Ductus venosus shunting in marmoset and baboon fetuses. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2005; 26:252-7. [PMID: 16116564 DOI: 10.1002/uog.1973] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
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.
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Affiliation(s)
- M Tchirikov
- Department of Obstetrics and Fetal Medicine, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany.
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Acharya G, Erkinaro T, Mäkikallio K, Lappalainen T, Rasanen J. Relationships among Doppler-derived umbilical artery absolute velocities, cardiac function, and placental volume blood flow and resistance in fetal sheep. Am J Physiol Heart Circ Physiol 2003; 286:H1266-72. [PMID: 14630636 DOI: 10.1152/ajpheart.00523.2003] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We hypothesized that umbilical artery (UA) absolute blood flow velocities measured by Doppler ultrasonography reflect placental volume blood flow (Q(UA)) and placental vascular resistance (R(UA)) in a late gestation fetal sheep model. In addition, we examined the relationships between umbilical artery absolute blood flow velocities and parameters of fetal cardiac function. Twenty-six sheep fetuses were instrumented at 112-132 days of gestation. After a 5-day recovery period, experiments were performed under general anesthesia in 16 normal fetuses, in 5 fetuses after maternal administration of phenylephrine, and in 5 fetuses after placental embolization. The Q(UA) and arterial blood pressures were measured using a transit-time ultrasonic flow probe and a catheter placed into the descending aorta, respectively. UA peak systolic velocity (PSV), end-diastolic velocity (EDV), time-averaged maximum velocity (TAMXV), pulsatility index (PI), mean velocity (V(mean)), fetal cardiac output, ventricular ejection forces, and the proportion of isovolumetric relaxation time (IRT%) in the cardiac cycle were measured with the use of Doppler ultrasonography. Significant positive linear correlations were found between UA EDV, TAMXV, and V(mean) versus Q(UA), whereas UA PI had a significant negative correlation with Q(UA). Significant negative correlations were shown between UA EDV, TAMXV, and V(mean) versus R(UA). A significant positive correlation was present between UA PI and R(UA). Doppler-derived UA parameters did not correlate with fetal arterial blood pressures, cardiac output, ventricular ejection forces or IRT%. In fetal sheep, Doppler-derived UA PI and absolute velocities, except PSV, are closely related to directly measured Q(UA) and R(UA), validating the use of noninvasive Doppler velocimetry in the assessment of placental circulation.
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Affiliation(s)
- Ganesh Acharya
- Department of Obstetrics and Gynecology, University Hospital of Northern Norway, N-9038 Tromsø, Norway.
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