Reversed End Diastolic Flow Research Articles

P37.10: Growth discordance and abnormal Doppler flow in a monochorionic triamniotic triplet pregnancy: A case report

Prevalence of spontaneous monochorionic triplet pregnancy is 1 in 7000 pregnancies with a 50–60% incidence of growth restriction. We report a case of 25 year old G1 P0 hospitalized at 24 6/7 weeks for one fetus with selective intrauterine growth restriction (IUGR) with absent or reversed end diastolic flow in the free loop of umbilical artery (FLUA). The estimated growths of the three fetuses were < 10%, 28% and 38%. There was no evidence of structural or functional cardiac abnormalities in any of the fetuses. There was no evidence of twin-twin transfusion syndrome. The patient was managed with bed rest, oxygen by nasal cannula, steroids and followed with daily biophysical profile and non-stress test, weekly Doppler and amniotic fluid evaluations. After eleven days, the IUGR fetus showed improvement in the ductus venosus and middle cerebral artery pulsatility index (PI) while FLUA showed mildly elevated PI. The plan was to prolong delivery of the triplets until after 32 weeks gestation, if possible. The antenatal course remained uneventful while on maternal oxygen therapy. At 32 weeks, the smaller fetus had grown to 37% percentile with all Doppler values within normal limits while on maternal oxygen and the delivery was conducted by scheduled cesarean section. The placental pathology showed a monochorionic placenta with one eccentric and two central insertions of the three vessel umbilical cords. The newborns weighed 1015 grams (g), 1350 g and 1530 g with normal Apgar score at 5 minutes. All of the triplets received continuous positive airway pressure and parenteral support in the newborn period. We conclude that oxygen therapy improved the Doppler flow pattern in the IUGR fetus of this triplet pregnancy and allowed for substantial growth in that fetus, thereby successfully prolonging the delivery date.

OP14.16: Cardiovascular changes and neonatal outcome in IUGR fetuses born to normotensive and preeclamptic mothers

Objectives: To compare the effects of maternal hyperoxygenation on the Doppler waveforms in twin pregnancies where one fetus has IUGR and absent or reversed end diastolic flow (ARED) in room air. Methods: Women with monochorionic diamniotic twin pregnancies with one IUGR fetus with ARED in room air between 2006 and 2008 who were hospitalized after 24 weeks gestation for close surveillance and bed rest were included in the study. All fetuses had structurally normal hearts. None had evidence of twin-twin transfusion syndrome. Measurements of Doppler flow pattern in middle cerebral artery (MCA), free loop of umbilical artery (FLUA) and ductus venosus (DV) were made in room air and then after breathing 60% oxygen by face mask for twenty minutes. Results: Seven twin pregnancies were included. The normal cotwin in each case had normal Doppler waveforms in room air and oxygen. All seven IUGR fetuses had ARED in room air and dilated DV size. In five patients, the FLUA normalized (PI < 1.75) after breathing 60% oxygen (mean PI = 3.21 in room air versus mean PI = 1.65 in oxygen). These five patients who had positive change with oxygen delivered an average of 5 weeks (range 3–14 weeks) after hospitalization. The other two patients who had no change in FLUA with oxygen and had abnormal MCA and DV in room air were delivered for obstetric indications within one day of the test. Conclusions: Maternal hyperoxygenation may be associated with normalization of the FLUA in fetuses with ARED after 24 weeks of gestation. A positive maternal hyperoxygenation test can select IUGR fetuses who have an abnormal FLUA in room air with a better prognosis and may be useful in postponing delivery in these fetuses with ARED.

OP14.15: The effects of the maternal hyperoxygenation test on twin pregnancies with one intrauterine growth restricted (IUGR) fetus

Objectives: To compare the effects of maternal hyperoxygenation on the Doppler waveforms in twin pregnancies where one fetus has IUGR and absent or reversed end diastolic flow (ARED) in room air. Methods: Women with monochorionic diamniotic twin pregnancies with one IUGR fetus with ARED in room air between 2006 and 2008 who were hospitalized after 24 weeks gestation for close surveillance and bed rest were included in the study. All fetuses had structurally normal hearts. None had evidence of twin-twin transfusion syndrome. Measurements of Doppler flow pattern in middle cerebral artery (MCA), free loop of umbilical artery (FLUA) and ductus venosus (DV) were made in room air and then after breathing 60% oxygen by face mask for twenty minutes. Results: Seven twin pregnancies were included. The normal cotwin in each case had normal Doppler waveforms in room air and oxygen. All seven IUGR fetuses had ARED in room air and dilated DV size. In five patients, the FLUA normalized (PI < 1.75) after breathing 60% oxygen (mean PI = 3.21 in room air versus mean PI = 1.65 in oxygen). These five patients who had positive change with oxygen delivered an average of 5 weeks (range 3–14 weeks) after hospitalization. The other two patients who had no change in FLUA with oxygen and had abnormal MCA and DV in room air were delivered for obstetric indications within one day of the test. Conclusions: Maternal hyperoxygenation may be associated with normalization of the FLUA in fetuses with ARED after 24 weeks of gestation. A positive maternal hyperoxygenation test can select IUGR fetuses who have an abnormal FLUA in room air with a better prognosis and may be useful in postponing delivery in these fetuses with ARED.

How often is the finding of absent or reverse end diastolic flow in the umbilical artery associated with fetal IUGR or oligohydramnios?

How often is the finding of absent or reverse end diastolic flow in the umbilical artery associated with fetal IUGR or oligohydramnios?

Antenatal umbilical Doppler abnormalities: an independent risk factor for early onset neonatal necrotizing enterocolitis in premature infants

Necrotizing enterocolitis (NEC) is the most common gastrointestinal (GI) emergency seen in neonatal units. Many factors have been considered as potentially important aetiologically, including gut ischaemia, sepsis and feeding. However, evidence remains equivocal. This study investigated whether preterm babies born to mothers with abnormal antenatal umbilical Dopplers (absent or reversed end diastolic flow--AREDF), that is exposed to antenatal gut ischaemia, are at an identical risk of developing NEC early in life, compared to babies born to mothers with normal Dopplers. All preterm (<or=32+6 week gestation) babies with no congenital anomaly, born to mothers resident in the county of Leicestershire in United Kingdom in 2001 and 2002 were identified using the Trent Neonatal Survey (TNS). Clinical data including the presence and severity of any NEC were extracted from the notes. Two hundred forty-three preterm babies who met the criteria were identified during the period. Babies in whom umbilical Dopplers were not available and babies that died in the first 48 h were excluded. Complete data was thus available for 206 of these babies. A strong relation between AREDF and subsequent development of NEC was noted in these babies (OR: 5.88, 95% CI: 2.41 to 14.34, p<0.0001). This association still held after adjustment for gestational age at birth (OR: 7.64, 95% CI: 2.96 to 19.70, p<0.0001) and after adjustment for birthweight for gestational age z-score (OR: 6.72, 95% CI: 2.23 to 20.25, p=0.0007). This study, based on a neonatal cohort, indicates that AREDF is an important independent risk factor for the production of NEC.

733: Ductus venosus reversed flow and arterial cord pH in fetuses delivered at < 30 weeks and weighing < 750 grams

Doppler flow velocitometry of Ductus venosus (DV) with reversed end-diastolic flow (RF) is considered an ominous sign in IUGR fetuses because it is thought to be related to irreversible decompensation and acidemia. It is not known, however, whether DVRF and acidemia are related in the preterm IUGR fetus. The aim of this study was to determine whether IUGR fetuses with DVRF delivered at < 30 weeks are acidemic at birth.

Predicting adverse neonatal outcome in severe fetal compromise: A pivotal role for estimated fetal weight Z scores

To identify significant predictors for adverse neonatal outcome in severe by compromised fetuses. Consecutive premature fetuses at between 25 and 32 weeks' with severe placental insufficiency were examined prospectively. Inclusion criteria were: singletons; normal anatomy; abnormal umbilical artery Doppler pulsatility index; abnormal cerebroplacental ratio; middle cerebral artery pulsatility index (PI) <or=2 standard deviations. We considered as independent potential predicting variables: absent or reversed end diastolic flow in umbilical artery, abnormal ductus venosus S/A ratio, absent or reversed flow during atrial contraction in the ductus venosus, and estimated fetal weight (EFW) Z score. Outcome parameters were: neonatal mortality and severe neonatal morbidity (Periventricular-Intraventricular Hemorrhage grade 03 or 04, Retinopathy of Prematurity stage 3 or 4, Periventricular Leukomalacia or Broncopulmonary Dysplasia). Univariate analysis for all potential predicting variables was performed. EFW Z score index showed the strongest association with mortality and there was no fetal death or Retinopathy of Prematurity in the group with EFW Z-score index below lower limit. There was no case of Cystic Periventricular Leukomalatia in these analyses. The area under receiver-operator characteristic curve was significant for EFW Z-score index. Our study suggests that EFW Z score is the strongest predictor of adverse neonatal outcome in severely compromised fetuses.

Reversed end‐diastolic flow in the umbilical artery at 10–14 weeks of gestation is associated with absent pulmonary valve syndrome

To determine the incidence of reversed end-diastolic flow (REDF) in the umbilical artery in high-risk first-trimester pregnancies and evaluate associated conditions. This was a prospective evaluation of the umbilical artery Doppler waveforms of 614 consecutive high-risk pregnancies between 10 and 14 weeks of gestation, to determine those with REDF. The associated anomalies and characteristics of these fetuses were then investigated. In 278/614 (45.3%) fetuses, there was positive end-diastolic flow in the umbilical artery; in 331/614 (53.9%) end-diastolic flow was absent and in 5/614 (0.8%) there was REDF. Three of the five fetuses with REDF had tetralogy of Fallot (TOF) with absent pulmonary valve syndrome (APVS) and a patent ductus arteriosus, and all three showed signs of cardiac failure, with reversed blood flow in the ductus venosus during atrial systole and generalized skin edema. Another fetus had a large ventricular septal defect and the remaining fetus had agenesis of the ductus venosus. Three fetuses had trisomy 18 and one had trisomy 13. REDF in the umbilical artery is very rare in early pregnancy and mostly occurs in association with major fetal vascular anomalies and cardiac defects, particularly TOF with APVS and patent arterial duct. We propose that the patency of the arterial duct in TOF with APVS leads to heart failure with subsequent demise early in pregnancy. Therefore, the frequent absence of the arterial duct observed in APVS in later pregnancy is more likely to be a result of early selection than a prerequisite for the development of this lesion as has been proposed previously.

Relationship between abnormal fetal testing and adverse perinatal outcomes in intrauterine growth restriction

This study was undertaken to compare the efficacy of nonstress test, biophysical profile, or abnormal Dopplers in predicting adverse perinatal outcomes in intrauterine growth restriction. Retrospective cohort study of intrauterine growth restriction (birthweight < fifth percentile for gestation) over a 7-year period. We excluded twins or fetuses with aneuploidy or congenital malformations. Abnormal antenatal testing were defined as: nonstress test that was nonreactive or with significant decelerations, biophysical profile less than or equal to 6, and abnormal Doppler as umbilical artery with absent or reversed end diastolic flow. The outcomes studied included: umbilical artery pH less than 7, respiratory distress syndrome, periventricular leukomalacia, grades 3-4 intraventricular hemorrhage, perinatal mortality, necrotizing enterocolitis, and a composite of at least 1 adverse outcome. Statistical analysis included bivariate and multivariable techniques. We identified 151 singleton pregnancies with intrauterine growth restriction meeting the inclusion criteria. On bivariate analysis significant variables associated with adverse outcomes were as follows: history of chronic hypertension, corticosteroid administration, and gestational age of delivery. These were adjusted by using logistic regression. The positive predictive values of abnormal Doppler for respiratory distress syndrome and the composite of adverse outcomes were 36% and 42% respectively. Of the testing modalities compared, only abnormal Doppler significantly predicted respiratory distress syndrome and the composite of adverse outcome. In cases of intrauterine growth restriction, the presence of abnormal Doppler is the best predictor of adverse perinatal outcome.

Impact of Enhanced External Counterpulsation on Peripheral Circulation

Enhanced external counterpulsation (EECP) is a noninvasive counterpulsation technique that reduces angina and improves exercise capacity in patients with coronary artery disease. Diastolic coronary perfusion is augmented by pneumatic compression of 3 sets of cuffs wrapped around the lower extremities. Although central hemodynamic changes are well investigated, almost no data exist about the changes of peripheral circulation during EECP. In this study, 12 patients with angina and angiographic evidence of coronary artery disease were treated for 1 hour with EECP. In these patients, peripheral artery disease was excluded by duplex sonography. The patients rested 1 hour before EECP in supine position, and they remained in that position for 1 hour after the procedure. Changes of flow volumes and flow pattern of the posterior tibial artery and the brachial artery were measured by sonography at the end of all 3 periods. Furthermore, we measured the concentration of circulating prostanoids at these 3 time points. Averaged flow volume of the posterior tibial artery decreased to 69% +/- 23% (P < .05) during EECP and increased to 133% +/- 34% (P < .05) of baseline 1 hour after the procedure. In contrast, the averaged flow volume of the brachial artery increased by 9% +/- 4% (P < .05) during EECP and returned to baseline values after EECP. The flow pattern of the posterior tibial artery showed a second early diastolic antegrade flow caused by the cuff inflation and a reverse end-diastolic flow after the deflation of the cuffs. These flow changes caused an increase of the pulsatility index by Gosling (397% during EECP), returning to baseline values in the recovery period. Plasma concentrations of circulating prostanoids showed no significant change during EECP. Thus, pedal flow volume decreased to approximately two thirds of baseline during EECP followed by reactive hyperemia even 1 hour after the procedure; however, this decreased perfusion triggered no change of the prostacyclin/thromboxane ratio and was well tolerated by all investigated patients. The observed 4-fold increase of the peripheral pulsatility index supports the thesis of increase of shear-stress-related improvement of endothelial function during EECP.

Doppler and birth weight Z score: predictors for adverse neonatal outcome in severe fetal compromise

BackgroundAn adequate placental perfusion is crucial for the normal growth and well being of the fetus and newborn. The blood flow through the placenta can be compromised in a variety of clinical situations, always causing important damage to the gestation. Our objective is to identify significant predictors for adverse neonatal outcome in severe fetal compromise.MethodsConsecutive premature fetuses at between 25 and 32 weeks with severe placental insufficiency were examined prospectively. Inclusion criteria were: (i) singletons (ii) normal anatomy; (iii) abnormal umbilical artery Doppler pulsatility index (PI); (iv) abnormal cerebroplacental ratio; (v) middle cerebral artery (MCA) PI < - 2SD ("brain sparing"); (vi) last Doppler examination performed within 24 hours prior to delivery. All 46 patients that met criteria and started the study were followed to the end. We considered as independent potential predicting variables: absent or reversed end diastolic flow in umbilical artery, abnormal ductus venosus S/A ratio, absent or reversed flow during atrial contraction in the ductus venosus and birth weight Z score. Outcome parameters were: neonatal mortality and severe neonatal morbidity.ResultsBackward stepwise logistic regression analysis was used to determine the optimal model for the prediction of neonatal mortality and severe neonatal morbidity. In this analysis birth weight Z score index showed the strongest association OR = 1,87 [1,17-2,99] with all neonatal outcome, all other independent variables were excluded for the optimal model. There was no mortality for the group with normal birth weight Z score.ConclusionOur study suggests that birth weight Z score is the strongest predictor of adverse neonatal outcome in severe placental insufficiencies. Such use of Z scores, allowing to get rid of gestational age or sex covariates could be extended to estimated fetal weight and might help in making important decisions in the management of compromised pregnancies.

Mean platelet volume: Association with adverse neonatal outcome

The aim of the study was to investigate on a possible association between maternal mean platelet volume (MPV) and oxygen-metabolic changes in pregnancies affected by altered maternal-fetal Doppler velocimetry. We considered the altered maternal-fetal Doppler velocimetry group (n = 57) pregnant women admitted to our Institution for a pregnancy complication associated to the event Pre-eclampsia (PE) and intrauterine growth retardation (IUGR), with altered Doppler velocimetry in the umbilical artery ( UA) (high pulsatility index, absence or reverse end diastolic flow (ARED), blood flow cephalisation) and/or bilateral increased resistance in uterine arteries. Out of these cases, 25 pregnancies were complicated by PE and 32 pregnancies were complicated by IUGR. We included 145 normotensive third trimester pregnant women as a normal maternal-fetal Doppler velocimetry control group. From all women, 20 ml of whole venous blood was obtained from the antecubital vein soon after Doppler velocimetry evaluation. MPV was significantly higher in women with abnormal Doppler velocimetry compared to those with normal Doppler velocimetry (8.0 fl [7.0–8.7] vs. 9.1 fl [8.0–10.6], <0.001. Values are median [interquartiles]). We performed a ROC curve in order to find an MPV cut-off able to predict an uneventful event in Doppler velocimetry compromised fetuses (neonatal O2 support > 48 hrs or intubation and/or pH < 7.2 at umbilical blood gas analysis (UBGA)). An MPV ≥ 10 fl was significantly related to the former diagnostic endpoints compared to that of non-compromised fetuses (sensitivity: 45%, specificity: 89.7%, 95 CI: 18.8–66, p < 0.01). Our study suggests that pregnancies affected by Doppler velocimetry alterations, an MPV value ≥ 10 fl may be associated with severe oxygen support and/or low UA ph at birth.

Management of small‐for‐gestational‐age twins with absent/reversed end diastolic flow in the umbilical artery: outcome of a policy of daily biophysical profile (BPP)

To evaluate a strategy of daily biophysical profile (BPP) for pregnancies with small-for-gestational-age twins and with absent or reversed end diastolic flow (AREDF) in the umbilical artery of one twin and to assess the latency interval between detection and delivery in monochorionic (MC) and dichorionic (DC) twin pregnancy. A search of the Fetal Medicine Database was carried out between 2000 and 2005 at a single tertiary centre to identify all cases with AREDF in the umbilical artery with one small-for-gestational-age twin. Active monitoring with daily BPP was undertaken, once the estimated fetal weights (EFW) was >or= 500 g and at a gestational age of >or= 24 weeks in both twins. Delivery was timed on the basis of an abnormal BPP, two equivocal BPP within 12 h or gestational age of >or= 32(+0) weeks. Twenty-two MC and 17 DC twin pregnancies were identified. There were no fetal losses in the viable actively monitored MC (19) and DC (13) twins. There was a longer latency interval in the MC group at 21.7 days versus 14.4 days in the DC group (p = 0.13). Delivery was indicated for an abnormal BPP (57.8% MC vs 30.8% DC). A strategy of daily BPP can be used to monitor preterm twin fetuses with AREDF, prolonging pregnancy with an acceptable perinatal outcome.

Management of Fetal Growth Restriction: An Evidence-Based Approach

This review provides an evidence-based approach to the management of fetal growth restriction (FGR). The management consists of the following components: appropriate fetal surveillance, timely intervention, and selective etiological management. Umbilical arterial (UA) Doppler sonography is the primary test. Supplementary tests include nonstress test (NST), amniotic fluid assessment, biophysical profile (BPP), and selective venous Doppler sonography. Ominous signs include UA absent or reverse end-diastolic flow, non-assuring NST, low BPP, and abnormal fetal venous flow patterns. An evidence-based clinical management guideline is included and individualization of care is recommended.

Comparison of perinatal outcome of growth-restricted fetuses with normal and abnormal umbilical artery Doppler waveforms

To evaluate the role of umbilical artery Doppler in growth- restricted fetuses. In a prospective observational study, 70 pregnant women with growth-restricted fetuses confirmed by ultrasound, were followed up with Doppler studies of the umbilical artery. The study group consisted of 35 women, where the Doppler waveform in the umbilical artery was compromised (either absent end diastolic flow [AEDF] or reversed end diastolic flow [REDF]). These were compared with an equal number of controls, where growth- restricted fetuses had normal doppler waveforms. Outcome measures were evaluated in both groups and analyzed. The periods of gestation at delivery were 27.2 +/- 3.5 weeks in group 1 and 37 +/- 3.3 weeks in-group II, respectively. Perinatal morbidity and mortality was significantly increased in the group with compromised umbilical artery blood group. Birth weight in group I was 742 +/- 126 grams and in group II was 1680 +/- 259 grams. This difference was statistically significant (P=0.0001). In comparison to AEDF, REDF fetuses had more morbidities. Perinatal mortality was also significantly increased in this group (P=0.001). Umbilical artery Doppler should be used in the management of growth-restricted fetuses. In those fetuses in normal Doppler, pregnancy can be prolonged. REDF is an indication for termination of pregnancy.

Intrauterine growth restriction and absent or reverse end-diastolic blood flow in umbilical artery (Doppler class II or III): A retrospective study of short- and long-term fetal morbidity and mortality

Absent or reverse end-diastolic flow (Doppler II/III) in umbilical artery is correlated with poor perinatal outcome, particularly in intrauterine growth restricted (IUGR) fetuses. The optimal timing of delivery is still controversial. We studied the short- and long-term morbidity and mortality among these children associated with our defined management. Sixty-nine IUGR fetuses with umbilical Doppler II/III were divided into three groups; Group 1, severe early IUGR, no therapeutic intervention (n = 7); Group 2, fetuses with pathological biophysical profile, immediate delivery (n = 35); Group 3, fetuses for which expectant management had been decided (n = 27). In Group 1, stillbirth was observed after a mean delay of 6.3 days. Group 2 delivered at an average of 31.6 weeks and two died in the neonatal period (6%). In Group 3 after a mean delay of 8 days, average gestational age at delivery was 31.7 weeks; two intra uterine and four perinatal deaths were observed (22%). Long-term follow-up revealed no sequelae in 25/31 (81%) and 15/18 (83%), and major handicap occurred in 1 (3%) and 2 patients (11%), respectively, for Groups 2 and 3. Fetal mortality was observed in 22% of this high risk group. After a mean period of follow-up of 5 years, 82% of infants showed no sequelae. According to our management, IUGR associated with umbilical Doppler II or III does not show any benefit from an expectant management in term of long-term morbidity.

Intrauterine growth restriction

Intrauterine growth restriction remains one of the major problems in obstetrics. Recent published literature on this problem is summarized in this review. Intrauterine growth restriction contributes disproportionately to neonatal mortality and morbidity in both preterm and term babies, and is a predisposing factor to major psychiatric sequelae such as depression, suicide and suicidal attempts. More evidence is accumulating to show that fetal Doppler changes of the ductus venosus and umbilical vein are good surrogate markers for fetal academia. The timing of delivery remains controversial, however. The Growth Restriction Intervention Trial showed that delayed delivery in those up to 30 weeks may be associated with lower rates of cerebral palsy and Griffiths development quotient under 70. In dichorionic twins, selective fetocide of one severe intrauterine growth restriction fetus in midtrimester twin pregnancies complicated by severe preeclampsia may abort the disease process and prolong the pregnancy. For monochorionic twins, the finding of intermittent absent or reversed end diastolic flow in the umbilical artery may be a manifestation of the transmission of the bi-directional waveforms of arterio-arterial anastomosis, but has been shown to be associated with an increased risk of intrauterine death in the growth restricted fetus and brain damage in the larger fetus. The timing of delivery of the preterm growth restricted fetus remains controversial. Intrauterine growth restriction with intermittent absent or reversed end diastolic flow in the umbilical artery of monochorionic twins poses difficulties in assessment.

A temporal model of deterioration in Doppler velocimetric parameters in fetal growth restriction related to cardiotocographic monitoring

The present study aimed to describe the time sequence of abnormal changes in Doppler velocimetric parameters and its relationship with fetal heart rate recorded in growth-restricted fetuses. Fifteen singleton pregnancies with an ultrasound diagnosis of fetal growth restriction (abdominal circumference < 2SD) were evaluated prospectively and longitudinally. Fetal outcome included four perinatal deaths, seven emergency Cesarean sections due to abnormal cardiotocogram (CTG) and four admissions to the neonatal intensive-care unit. We observed 'early' Doppler changes (15 to 10 days prior to delivery) in the umbilical artery (UA), middle cerebral artery (MCA) and cerebroplacental ratio. 'Late' Doppler changes included absent or reverse end-diastolic flow in the UA, high resistance in the ductus venosus (DV) and decrease of umbilical venous blood flow. These changes appeared in 10% of cases 4-7 days prior to delivery and in up to 40% of cases on the day of delivery. Although occurring less frequently, umbilic...

Pseudo-arterio-arterial anastomoses in twin–twin transfusion syndrome

It has recently been claimed that fetoscopic recognition of a haemodynamic equator within an arterio-arterial anastomosis (AAA) suggests minimal net intertwin flow. This was based on blood from one fetus being dark and from the other bright red, the boundary between them reciprocating with the fetal heart beats. However, bright red indicates that the blood had passed through a cotyledon and been freshly oxygenated, which should be impossible in an AAA. We applied a computer model of chorionic vessels to determine a configuration that reproduced this phenomenon. A previously published TTTS model was extended to provide placental detail in a segment containing four cotyledons of each placenta supplied by three generations of placental arteries and veins. Reciprocating flow is not unique to AAAs. It also occurs in the chorionic arteries of any cotyledon deprived of its venous outflow, in a similar manner to that in which reverse end-diastolic flow occurs in umbilical arteries when whole placental resistance is high. If venous return from the common chorionic vein in the recipient (draining the venous end of an AVA) is blocked as might happen after laser, there can be bidirectional flow from one umbilical artery insertion, through two cotyledons to the other insertion. We define this phenomenon as a pseudo-AAA (PAAA). The inclusion of two cotyledons in this path means that its resistance cannot match the low flow resistance of a true AAA, and transmission of the contralateral pulsatile pattern is absorbed in the cotyledons. Thus, PAAA Doppler patterns differ from true AAA patterns in that two sets of systolic peaks, one forward and one reverse, can be discerned in true AAAs but only one in PAAAs. We demonstrate how venous occlusion of an arterio-venous anastomosis may produce a pseudo-AAA colour equator at endoscopy. However, visual observation of reciprocating flow is not sufficient to define a vessel as a true AAA which instead requires ultrasonical identification of two systolic patterns.

Absent or reverse end-diastolic flow in the umbilical artery: intellectual development at school age

This study was designed to establish whether, in growth-retarded fetuses, absent or reverse end-diastolic (ARED) flow velocity in the umbilical artery can be predictive of an increased incidence of long-term neurological and intellectual impairment. A total of 14 children with intra-uterine growth retardation (IUGR) and ARED flow in the umbilical artery and 11 children without this velocimetric pattern were examined by pediatric neuropsychiatrists at a median age of 8.7 years to evaluate and compare their neurological and intellectual development. The incidence of major neurological sequelae was higher in the children with ARED velocity in the umbilical artery (21%) than in those without this velocimetric pattern (9%), as was the incidence of mild neurological sequelae (35% versus 27%). No differences in mean intelligence quotient (IQ) as evaluated by mean of Intelligence Scale for Children-Revised (WISC-R) scale were found between the two groups of children at school age. Our data demonstrate that Doppler velocimetry in the umbilical artery is a reliable predictor for neurological sequelae when ARED flow is present but cannot be considered a good predictor of intellectual performance at school.