End-diastolic Flow Velocity Research Articles

Ocular and retrobulbar blood flow in ocular hypertensives treated with topical timolol, betaxolol and carteolol.

The purpose of this study was to evaluate the effect of topical timolol 0.5%, betaxolol 0.5% and carteolol 2% on the blood flow velocity of the central retinal artery (CRA), the posterior ciliary artery (PCA) and the ophthalmic artery (OA) in patients with ocular hypertension. A group of 14 patients with ocular hypertension and a group of 11 normals were studied. The color Doppler was used to measure the peak systolic flow velocity (PSFV) and the end diastolic flow velocity (EDFV) of the CRA, the PCA and the OA in the normals and in the patients. The normals were under no treatment, while the patients were studied before and after treatment with topical timolol 0.5%, betaxolol 0.5% and carteolol 2%. In the systolic phase, there was a significant increase in the flow velocity of the CRA with all three drugs. In the diastolic phase of the CRA, the increase was significant for timolol 0.5% and carteolol 2% but not for betaxolol 0.5%. The flow velocity of the PCA and OA remained unchanged. In this study of 14 patients with ocular hypertension, topical timolol 0.5%, betaxolol 0.5% and carteolol 2% led to a significant increase in the flow velocity of the CRA without creating a steal or decrease in the flow velocity of the PCA.

Comparison of visually evoked peak systolic and end diastolic blood flow velocity using a control system approach

Transcranial Doppler sonography measures blood flow velocity in basal cerebral vessels with high accuracy. For quantification, time averaged mean blood flow velocities are used most because the peak systolic and end diastolic blood flow velocities mark the velocity extremes of one heart cycle. It is known, from hemodynamic measurements of the neurovascular coupling mechanism, that the end diastolic velocity is more sensitive for change in hemodynamics than the peak systolic velocity. Thus, we used a recently introduced control system approach to compare both indices for their use in functional transcranial Doppler tests focusing on hemodynamics of blood flow velocity change. We enrolled 65 healthy young volunteers without a medical history of cardiovascular risk factors, and performed a visual stimulation test. Peak systolic and end diastolic maximal blood flow velocities were used after transformation to relative data for control-system analysis. Due to Doppler artefacts, 95% of peak systolic and 86% of end diastolic data sets were analyzed. Results showed statistically significant differences for resting blood flow velocity and the control system parameter gain, attenuation and rate time, whereas the parameters’ natural frequency and time delay were equal. Increase in relative blood flow velocity in the posterior cerebral artery due to visual-cortical stimulation was higher in end diastolic values than peak systolic data. Using a complex visual stimulation paradigm, the higher sensitivity of the end diastolic index is of no practical use. Being less influenced by Doppler artefacts, the peak systolic velocity index is more feasible for control-system analysis of dynamic blood flow regulation. (E-mail: Manfred.Kaps@Neuro.med.uni-Giessen.de)

Interobserver and intraobserver reliability of venous transcranial color-coded flow velocity measurements.

Venous transcranial color-coded duplex sonography is a new technique for noninvasive evaluation of the intracranial venous system. However, the interobserver and intraobserver reliability of this method is unclear. In 23 healthy volunteers (30 +/- 7.3 years of age), the deep middle cerebral vein (dMCV), basal vein (BV), vein of Galen (VG), and straight (SRS), transverse (TS), and superior sagittal (SSS) sinuses in addition to the arterial segments of the circle of Willis were insonated through the temporal bone window on 2 consecutive days by 2 experienced examiners. The examiners were blinded to each other's results. The interobserver and intraobserver reliability was calculated using a method described by Bland and Altman, resulting in 2-SD confidence intervals. Non-angle-corrected and angle-corrected systolic and end diastolic venous flow velocities (FV) were in good accordance with published normal values, ranging between 8.6 and 19.2 cm/s. The interobserver reliabilities for non-angle-corrected systolic FVs in the dMCV, BV, VG, SRS, and TS were +/- 1.8, 2.4, 2.6, 3.3, and 4.6 cm/s; for angle-corrected systolic FVs, the interobserver reliabilities were +/- 2.5, 3.1, 13.9, 11.6, and 7.7 cm/s. The intraobserver reliabilities for non-angle-corrected systolic FVs in the dMCV, BV, VG, SRS, and TS were +/- 2.9, 3.2, 2.6, 3.2, and 6.1 cm/s; for angle-corrected systolic FVs, the intraobserver reliabilities were 3.2, 3.7, 13.9, 11.6, and 7.5 cm/s. Angle correction was not attempted for the SSS. The interobserver and intraobserver reliabilities for systolic FVs in the SSS were +/- 3.3 and +/- 3.3 cm/s, respectively. Intracranial venous FVs can be measured with a high interobserver and intraobserver reliability in healthy human subjects. Intraobserver reliability was higher for cerebral veins than for dural sinuses, predisposing them for follow-up examinations; however, angle correction for venous FVs in the VG and the SRS is not advisable.

Abnormal Doppler velocimetry and blood flow volume in the middle cerebral artery in very severe intrauterine growth restriction: is the occurence of reversal of compensatory flow too late?

To determine the time course of quantified volumetric flow and pulsatility index changes in the middle cerebral arteries of severe intrauterine growth restricted fetuses with absent or reversed end diastolic flow velocities (AREDFV) on umbilical artery Doppler with a view to defining the threshold for early intervention before the onset of reversal of adaptation. Fetal growth clinic of a large UK teaching hospital. Seventeen severe intrauterine growth restricted (AC < third centile for gestation and gender) fetuses with abnormal umbilical artery Doppler velocimetry and oligohydramnios (amniotic fluid index <third centile for gestation). One to three daily Doppler velocimetry and quantified volume flow of the middle cerebral artery Doppler velocimetry of the umbilical arteries and daily cardiotocography. Reversal of adaptation occurred in eight fetuses, four of which ended as stillbirths and four as neonatal deaths. In two of these fetuses, this had already occurred before the diagnosis of intrauterine growth restriction. In the others, the onset was rapid and difficult to predict. Volume flow in the middle cerebral arteries decreased in those fetuses exhibiting reversal of adaptation but rose in the nine in which compensatory Doppler indices persisted. The decrease in volume flow occurred before the onset of reversal of adaptation in the pulsatility index. In the fetuses exhibiting reversal of adaptation, the rise in the pulsatility index was consistent over 48 hours compared with the physiological fluctuations in pulsatility index in some fetuses where the rise was only for 24 hours followed by a fall. Quantified volume flow fell in the fetuses before reversal of adaptation set-in. The umbilical artery Doppler indices fluctuated between absent and reversed end diastolic velocities within the same fetus irrespective of the changes in the middle cerebral artery Doppler indices. Reversal of adaptation is of sudden onset and is associated with poor prognosis. Predicting its occurrence on Doppler indices is difficult as the changes may be very rapid. However, volume flow changes appear to be slower and of earlier onset than the pulsatility index changes. This may therefore be a more useful tool in predicting imminent reversal of adaptation and therefore early delivery.

Abnormal Doppler velocimetry and blood flow volume in the middle cerebral artery in very severe intrauterine growth restriction: is the occurrence of reversal of compensatory flow too late?

Objectives To determine the time course of quantified volumetric flow and pulsatility index changes in the middle cerebral arteries of severe intrauterine growth restricted fetuses with absent or reversed end diastolic flow velocities (AREDFV) on umbilical artery Doppler with a view to defining the threshold for early intervention before the onset of reversal of adaptation. Setting Fetal growth clinic of a large UK teaching hospital. Sample Seventeen severe intrauterine growth restricted (AC<third centile for gestation and gender) fetuses with abnormal umbilical artery Doppler velocimetry and oligohydramnios (amniotic fluid index <third centile for gestation). Methods One to three daily Doppler velocimetry and quantified volume flow of the middle cerebral artery Doppler velocimetry of the umbilical arteries and daily cardiotocography. Results Reversal of adaptation occurred in eight fetuses, four of which ended as stillbirths and four as neonatal deaths. In two of these fetuses, this had already occurred before the diagnosis of intrauterine growth restriction. In the others, the onset was rapid and difficult to predict. Volume flow in the middle cerebral arteries decreased in those fetuses exhibiting reversal of adaptation but rose in the nine in which compensatory Doppler indices persisted. The decrease in volume flow occurred before the onset of reversal of adaptation in the pulsatility index. In the fetuses exhibiting reversal of adaptation, the rise in the pulsatility index was consistent over 48 hours compared with the physiological fluctuations in pulsatility index in some fetuses where the rise was only for 24 hours followed by a fall. Quantified volume flow fell in the fetuses before reversal of adaptation set-in. The umbilical artery Doppler indices fluctuated between absent and reversed end diastolic velocities within the same fetus irrespective of the changes in the middle cerebral artery Doppler indices. Conclusion Reversal of adaptation is of sudden onset and is associated with poor prognosis. Predicting its occurrence on Doppler indices is difficult as the changes may be very rapid. However, volume flow changes appear to be slower and of earlier onset than the pulsatility index changes. This may therefore be a more useful tool in predicting imminent reversal of adaptation and therefore early delivery.

Influence of poststenotic collateral pressure on blood flow velocities within high-grade carotid artery stenosis: Differences between morphologic and functional measurements

Purpose: The driving force for blood flow through a high-grade stenosis in the internal carotid artery can be expressed as the pressure gradient over the stenosis itself, which, however, might be reduced by the back pressure exerted by distal collateral vessels. Theoretically the maximum blood flow velocity as a measure of the functional grade of obstruction may therefore be lower than what is expected from morphologic gradations of the stenosis. This study was designed to test prospectively the influence of intracranial collateral vessels on blood flow velocities within high-grade internal carotid artery stenoses. Patients and Methods: Forty-five consecutive patients (age 66 ± 11) with high-grade internal carotid artery stenoses were investigated before and during carotid endarterectomy. The preoperative investigations included duplex ultrasound scanning of the neck vessels, transcranial Doppler scanning for assessment of collateral flow to the middle cerebral artery and angiography. Carotid endarterectomy was performed with patients under deep general anesthesia without a shunt. Systolic and diastolic internal carotid artery blood pressures were measured before and during intraoperative cross-clamping (ie, stump pressure) of the carotid arteries. Results: Within high-grade internal carotid artery stenoses, maximum systolic and end-diastolic blood flow velocities showed a significant inverse correlation to the corresponding systolic and diastolic stump blood internal carotid artery blood pressures. All patients with spontaneous collateral flow to the ipsilateral anterior part of the circle of Willis were divided into a group with relatively high and another one with low end-diastolic blood flow velocities. The stump pressure was significantly lower in patients with high end-diastolic blood flow velocities in spite of the fact that the mean angiographic grade of stenosis did not differ significantly between the groups. Conclusions: Flow velocities within a high-grade internal carotid artery stenosis are inversely dependent on the stump pressure, that is the poststenotic collateral perfusion pressure. This should be taken into consideration in case of discrepancies between angiography and ultrasound outcome. (J Vasc Surg 2001;34:263-8.)

Effects of phenobarbital on cerebral blood flow velocity after endotracheal suctioning in premature neonates.

To examine the effect of phenobarbital administration on anterior cerebral artery blood flow velocity before and after endotracheal suctioning in premature neonates. Transcutaneous PO(2) (TcPO(2)), heart rate, mean arterial blood pressure (MABP), and Doppler velocimeter blood flow of the left anterior cerebral artery were measured before and immediately after 3 consecutive endotracheal suctioning procedures in premature neonates. Intravenous phenobarbital (20 mg/kg) was administered immediately after the first procedure. Neonatal intensive care unit. Nine neonates with a mean birth weight of 807 g (range, 620-1060 g) and a mean gestational age of 27 weeks (range, 25-30 weeks) were studied at age 8 to 12 hours. Transcutaneous PO(2) decreased in response to endotracheal suctioning at each of the suctioning procedures before and after phenobarbital was given (P<.001). Changes in heart rate were not observed. There were increases in MABP and area under the velocity curve (AUVC) per minute in response to endotracheal suctioning before but not after phenobarbital administration (P=.046). Use of phenobarbital lowered the overall peak systolic blood flow velocity in response to endotracheal suctioning (P =.02, analysis of variance, interactions for the effect of phenobarbital therapy on the response to suctioning). Changes in end-diastolic blood flow velocity were not observed. There were decreases in the differences before and after endotracheal suctioning for MABP at 2 and 4 hours and for AUVC and peak systolic blood flow velocity 4 hours after phenobarbital was given (P =.04). In very low-birth-weight neonates, endotracheal suctioning is associated with decreases in TcPO(2) and increases in MABP and AUVC. Treatment with phenobarbital attenuates the increases in MABP and AUVC but not the decreases in TcPO(2) after endotracheal suctioning.

Color Doppler imaging of untreated and irradiated choroidal melanomas.

We examined untreated and irradiated choroidal melanomas with color Doppler imaging (CDI), a noninvasive method providing quantitative measures of blood flow, to determine if the tumor vessel damage associated with irradiation can be detected using this technology. CDI was performed on 122 untreated and 76 previously irradiated tumors using a Q2000 color Doppler ultrasound unit. Spectral analysis was performed on all detectable vascular regions within the tumor to obtain estimates of the peak systolic and end diastolic flow velocities and resistive index ((syst-diast)/syst). Vessels were detected in 93% of the untreated tumors and in 63% of the treated tumors (p<0.001, X2), and the median number of vascular regions found was higher among untreated tumors (3 vs 1, p=0.001, Wilcoxon Rank Sum). The effect of treatment status on the detection of tumor vessels was significant (p=0.039), controlling for age, sex, largest tumor pretreatment diameter, and tumor height at CDI in a logistic regression model. Mean resistive index was lower in the untreated tumors (0.53 vs 0.58, p=0.0050), controlling for tumor height and other covariates in an analysis of variance. On examination with CDI, irradiated tumors had fewer detectable vascular regions and greater resistance to flow than untreated tumors, a pattern consistent with known radiation effects.

Infants of Women With Severe Early Pre-Eclampsia: The Effect of Absent End-Diastolic Umbilical Artery Doppler Flow Velocities on Neurodevelopmental Outcome

Umbilical artery Doppler flow velocity waveform studies were performed over a period of 4 y on 242 women with severe pre-eclampsia before 34 wk gestation. Sixty-eight (28%) had absent end-diastolic umbilical artery Doppler flow velocities. One hundred and ninety-three infants survived to hospital discharge and were followed at 6-monthly intervals until 48 mo of age. The mean corrected developmental quotient was 94 +/- 8 at 24 mo of age and 87 +/- 9 at 48 mo. Ninety-two percent of the infants had a developmental quotient of >80 at 24 mo and 72% at 48 mo of age. This decline is thought to be due to the impact of social circumstances. There were no differences between the developmental quotients of the infants with normal and those with absent end-diastolic umbilical artery Doppler flow velocities at either 24 or 48 mo of age. At 24 mo of age, infants with absent end-diastolic umbilical artery Doppler flow velocities scored lower in the Performance subscale test (p = 0.03). The developmental quotients of infants from poorer socioeconomic backgrounds were significantly lower than those living in more privileged circumstances. At 48 mo, 153 (97%) of the children presented with normal gross motor development. Four infants had cerebral palsy. No differences were noted in the motor outcomes between the infants of women with normal umbilical artery waveforms and those with absent end-diastolic umbilical artery Doppler flow velocities.

Reversed end diastolic flow velocity in viable fetuses: is there time to wait for the effect of corticosteroids before delivery?

In severely pre-term, but viable fetuses with reversed end diastolic flow velocity in the umbilical artery, there is time for the effects of corticosteroids before delivery, unless fetal distress occurs.

Superior mesenteric artery blood flow velocity in small for gestational age infants of very low birth weight during the early neonatal period.

In order to elucidate intestinal blood flow after birth in infants with intrauterine growth retardation, we measured superior mesenteric artery blood flow velocity in uncomplicated small for gestational age infants with a birth weight of < 1500 g by pulsed Doppler ultrasound in days 1 to 7 of life. Peak systolic blood flow velocity, time-averaged mean blood flow velocity and end-diastolic blood flow velocity in the superior mesenteric artery significantly increased with time. The resistance index and relative vascular resistance in the superior mesenteric artery significantly decreased after birth. Compared with gestational age matched appropriate for gestational age infants and birth weight matched appropriate for gestational age ones, peak systolic blood flow velocity, time-averaged mean blood flow velocity and end-diastolic blood flow velocity in the superior mesenteric artery were lower in the small for gestational age infants. The difference between the small for gestational age group and the gestational age matched appropriate for gestational age group was statistically significant. The resistance index and relative vascular resistance in the superior mesenteric artery tend to be higher in the small for gestational age group than in the appropriate for gestational age groups. In conclusion, although intestinal blood flow velocity in infants with intrauterine growth retardation increases after birth, it is lower than appropriate for gestational age infants during the early neonatal period.

Neonatal and neurodevelopmental outcome in infants born before 30 weeks of gestation with absent or reversed end-diastolic flow velocities in the umbilical artery.

The objective of our study was to examine the outcome of infants born at a gestational age < 30 weeks with absent or reversed end-diastolic flow velocity (AREDFV) in the umbilical artery in comparison with gestational age-matched eutrophic controls. A group of 40 infants who had AREDFV were matched for gestational age and date of birth with 40 appropriate for gestational age infants. Perinatal outcome variables were retrospectively reviewed. In 16 out of the 40 matched pairs, a standardized neurological examination was done and, depending on age, the Kaufman Assessment Battery for Children or the Bayley Scales of Infant Development were applied at a corrected age of 13 to 100 months to assess neurodevelopmental outcome. The results were compared using Fisher's Exact Test or Mann Whitney U Tests as appropriate. In the AREDFV group, 26/40 (65%) survived until discharge compared to 39/40 (97.5%) in the control group (P < 0.001). AREDFV was associated with a higher rate of chronic lung disease, retinopathy of prematurity > or = grade III and impaired intestinal motility. More AREDFV infants suffered from permanent neurological sequelae compared with control infants: 44% versus 25% were mentally retarded (P = 0.033), and 38% versus 19% showed severe motor impairment (P = 0.073). Absent or reversed end-diastolic flow velocity is not only associated with a higher mortality and morbidity during the neonatal period, but the surviving infants of this high risk group have an increased risk for mental retardation and severe motor impairment as compared with appropriate for gestational age preterm infants of the same gestational age.

Color Doppler Imaging of the Orbital Vessels in Behçet’s Disease

Objective: To investigate blood flow velocity changes, pulsatility and resistivity index values of orbital vessels in Behçet’s disease with or without ocular involvement (groups I and II) and healthy volunteers (group III). Methods: Twenty-five eyes in the first group, 24 eyes in the second group and 24 eyes in the third group were examined by using color Doppler imaging. Peak systolic and end-diastolic blood flow velocity measurements, pulsatility and resistivity index values were measured in ophthalmic, central retinal, nasal and temporal ciliary arteries and the central retinal vein. Results: The end-diastolic blood flow velocity measurements in all arteries were significantly higher in groups II and III than in group I, but resistivity and pulsatility indexes of all arteries were higher in group I than the other two groups. There was no significant difference in blood flow velocity of the central retinal vein in the three groups. Conclusion: Detection of increased vascular resistance of orbital vessels may predict the diagnosis of ocular involvement in Behçet’s disease.

WS15: Second and third trimester Doppler II WS15‐01High pathological Doppler flow findings (absent or reverse enddiastolic flow) and fetal outcome

BackgroundReversed enddiastolic Doppler flow velocity waveforms on umbilical velocimetry is regarded to be associated with catastrophical perinatal outcome with a high perinatal mortality ranging from 35% to 100%. This study focused on the differences of fetal morbidity and mortality between the cases with reverse flow and other Doppler flow velocity waveforms.MethodDuring a 10‐year period we found 30 cases with reverse flow in the umbilical artery or fetal aorta (gr. I), we selected 30 cases with absent end diastolic velocities (gr. II), 30 cases with high A/B‐ratio (gr. III) and 30 cases with normal A/B‐ratio (gr. IV). All cases in this study were patients with similar para, gravida, maternal age and gestational ages by delivery (≤ 36 weeks).ResultsThe fetuses with reverse flow showed the highest perinatal mortality of 27% (7% in the gr. II, 10% in the gr. III and 0% in the gr. IV). In the gr. I the neonatal morbidity of 78% was also the highest (59% in the gr. II, 36% in the gr. III and 30% in the gr. IV). 80% of intrauterine fetal death (IUFD) were within this group, while no IUFD has been found in the gr. IV. Furthermore, the incidence of cerebral haemorrhage by the neonates in the gr. I (28%) was also much higher than those in the gr. III (4%) and IV (0%).ConclusionsOur study suggests that reverse flow represents severe fetal condition with the highest perinatal mortalities. The fetal outcome in cases with reverse flow is further worse than those with absent end diastolic flow velocity waveforms. A highest morbidity was also observed by those fetuses, especially high incidences of cerebral haemorrhage. Colour Doppler‐sonography is a very useful tool to identify high risk pregnancy leading worse perinatal outcome and allows to select worst perinatal prognosis if reverse end diastolic flow is detected.

Flow velocity and flow volume measurements in the extracranial carotid and vertebral arteries in healthy adults: reference data and the effects of age

To establish reference data and to investigate the development of haemodynamics in the extracranial carotid and vertebral arteries, we performed a prospective study in 78 age- and gender-matched healthy adults from 20 to 85 y old. Angle-corrected flow velocities and luminal diameters were measured and waveform parameters and flow volumes calculated in all the arteries. Side-to-side differences and the influence of age on these parameters were also investigated. In the common carotid arteries, the internal carotid arteries and the vertebral arteries (CCA, ICA and VA, respectively) all flow velocities decreased significantly during ageing. The luminal diameter remained constant in all the carotid arteries, but increased slightly with age in the VA. An age-related decline of intravascular flow volume was observed in the ICA. Due to a pronounced decrease in end-diastolic flow velocity, the resistance index decreased in ICA and VA during ageing. There were no significant side-to-side differences in flow velocities and flow volumes in any of the extracranial arteries. The luminal diameters of the CCA, ICA and ECA were significantly smaller in women than in men. No relevant gender-related differences in flow velocities or waveform parameters were found in the extracranial arteries. There was no gender-linked difference in the flow volumes of the brain-feeding arteries and, in the ECA, flow volumes were significantly higher in men. Reference data on all flow velocities and waveform parameters, luminal diameters and flow volumes were established for different age groups between 20 and 85 y old. These data allow us to outline the development of cerebral haemodynamics during “benign ageing” and to utilise flow volume measurements in clinical practice, especially in patients with cerebrovascular diseases.

WS17‐09Doppler flow measurements and neuromotoric morbidity

BackgroundAbsent enddiastolic flow (AEDF) velocities are associated with fetal distress and adverse fetal outcome. The aim of this study was to evaluate perinatal findings of fetuses with an AEDF in fetal vessels and to investigate the neurological long‐term‐outcome.MethodThe analytical program ‘Munich functional developmental diagnostics’ (MFDD) was applied to the 90 children at different time intervals. The results of 40 children with an AEDF (Gr. I) and 20 children with pathological S/D‐Ratio (Gr. II) were compared to the group of 30 children with normal Doppler‐flow‐findings (Gr. III) with the same pregnancy weeks at birth.ResultsThe rate of C‐section (92% vs. 71% vs. 36%), birthweight (1140g vs. 1725g vs. 2570g), 5′min. APGAR‐Score (31% vs. 5% both) were significantly different in three groups. Brain sparing effect in the middle cerebral arteries was found in 81% in Gr. I, in 21% Gr. II and only 8% in Gr. III. At the time of neurological assessment the age of children was between 12 and 36 months. The developmental age for each functional category was evaluated and the difference between corrected age and developmental age was calculated. In 33% of all infants with a AEDF had a pathological neuromotoric development vs. 22% in Gr. II and only 15.3% in Gr. III.ConclusionsThe children with pathological Doppler‐flow‐measurements during pregnancy have not only very high risk of perinatal abnormality but also show a distinctly increased risk of impaired growth and neurodevelopmental disability comparing to the cases with a normal Doppler‐flow‐finding. Most of these fetuses showed brain‐sparing effect. These aspects are very important to be discussed with the parents before the definitive perinatal decision is made.

Development of the placental villous tree and its consequences for fetal growth

Co-ordinated development of the fetal villous tree of the placenta is necessary for continued fetal growth and well-being. Before fetal viability, blood vessel development within the developing immature intermediate villi (IIV) is characterized by branching angiogenesis, such that the placenta expands to produce 10–16 generations of stem villi. Once fetal viability is attained, a developmental switch occurs to form large numbers of gas-exchanging terminal villi (TV) by non-branching angiogenesis in mature intermediate villi (MIV). Several growth factors, including vascular endothelial growth factor (VEGF), placenta growth factor (PlGF), angiopoietins, and angiostatins are produced within the villi and act locally, via their receptors, to control angiogenesis. Their relative contributions to placental vascular development are not fully understood at the present time. Severe early-onset intrauterine growth restriction (IUGR) is characterized by absent/reversed end-diastolic flow velocity (ARED) in the umbilical arteries, leading to fetal hypoxia, acidosis and a substantial rise in perinatal mortality and morbidity. The placentas from such cases show a deficit in peripheral villous development, which may be perpetuated by the effects of oxygen (delivered by maternal blood into the intervillous space) upon VEGF-directed angiogenesis, the so-called ‘placental hyperoxia’ theory of villous maldevelopment. Trophoblast apoptosis is a significant feature of early-onset IUGR and may explain poor flow-independent transfer of nutrients to the fetus. Finally, since transgenic mouse studies highlight the importance of trophoblast-derived transcription factors for placental villous (labyrinth) development, it is possible that the villous trophoblast controls the orderly development of the underlying mesoderm and blood vessels into the fetal villi.

Long-term outcome in twin-twin transfusion syndrome treated with serial aggressive amnioreduction

<h2>Abstract</h2> <b>Objective:</b> The purpose of this study was to determine long-term outcomes among pregnancies complicated by twin-twin transfusion syndrome and treated in a tertiary center with serial aggressive amnioreduction. <b>Study Design:</b> Thirty-three pregnancies with a diagnosis of twin-twin transfusion syndrome were treated with ≥1 amnioreduction. The perinatal outcome was assessed according to 15 parameters, whereas the main outcome at age ≥2 years was the absence of cerebral palsy. <b>Results:</b> Gestational age at diagnosis ranged from 14.5 to 33 weeks' gestation (median, 20.6 weeks' gestation), whereas gestational age at delivery was between 18.5 and 37 weeks' gestation (median, 30.5 weeks' gestation). The number of amnioreductions per pregnancy ranged from 1 to 15 (median, 2). At initial examination hydrops of the recipient and absence of the end-diastolic velocity of the umbilical artery in one of the twins were associated with poor prognosis. Fifty-one (77%) twins were born alive. At 24 months after birth both infants from 57% of the pregnancies (19/33) were alive, whereas at least one infant from 70% of the pregnancies (23/33) was alive. Thirty-three infants (78% of the survivors) were older than 36 months at last follow-up. Cerebral palsy was diagnosed in 2 of 42 infants (4.7%). One of the affected infants was born after the fetal death of the cotwin; the other infant was born with congenital cardiac malformations. <b>Conclusions:</b> In the group of fetuses in which both twins were delivered alive after 27 weeks' gestation without congenital malformations and survived the neonatal period, no major neurologic handicaps developed in any of the infants. At initial examination both hydrops of the recipient and absence of end-diastolic flow velocity waveforms of the umbilical artery in one of the twins were poor prognostic signs. (Am J Obstet Gynecol 2000;183:211-7.)

Long-term outcome in twin-twin transfusion syndrome treated with serial aggressive amnioreduction

Objective: The purpose of this study was to determine long-term outcomes among pregnancies complicated by twin-twin transfusion syndrome and treated in a tertiary center with serial aggressive amnioreduction. Study Design: Thirty-three pregnancies with a diagnosis of twin-twin transfusion syndrome were treated with ≥1 amnioreduction. The perinatal outcome was assessed according to 15 parameters, whereas the main outcome at age ≥2 years was the absence of cerebral palsy. Results: Gestational age at diagnosis ranged from 14.5 to 33 weeks’ gestation (median, 20.6 weeks’ gestation), whereas gestational age at delivery was between 18.5 and 37 weeks’ gestation (median, 30.5 weeks’ gestation). The number of amnioreductions per pregnancy ranged from 1 to 15 (median, 2). At initial examination hydrops of the recipient and absence of the end-diastolic velocity of the umbilical artery in one of the twins were associated with poor prognosis. Fifty-one (77%) twins were born alive. At 24 months after birth both infants from 57% of the pregnancies (19/33) were alive, whereas at least one infant from 70% of the pregnancies (23/33) was alive. Thirty-three infants (78% of the survivors) were older than 36 months at last follow-up. Cerebral palsy was diagnosed in 2 of 42 infants (4.7%). One of the affected infants was born after the fetal death of the cotwin; the other infant was born with congenital cardiac malformations. Conclusions: In the group of fetuses in which both twins were delivered alive after 27 weeks’ gestation without congenital malformations and survived the neonatal period, no major neurologic handicaps developed in any of the infants. At initial examination both hydrops of the recipient and absence of end-diastolic flow velocity waveforms of the umbilical artery in one of the twins were poor prognostic signs. (Am J Obstet Gynecol 2000;183:211-7.)

Relationship between the effect of carbon dioxide inhalation or nilvadipine on orbital blood flow in normal-tension glaucoma.

To investigate the relationship between the effect of carbon dioxide (CO2) inhalation or oral nilvadipine, a calcium-channel blocker, on orbital blood flow in patients with normal-tension glaucoma, as determined by color Doppler imaging. Sixteen patients with normal-tension glaucoma (mean age, 55.6+/-9.8 years; male:female ratio, 3:13) underwent color Doppler imaging to measure the resistance index, and peak systolic and end-diastolic blood flow velocities of the ophthalmic artery, central retinal artery, and nasal and temporal short posterior ciliary arteries. Measurements were taken before and during CO2 supplementation sufficient to increase the end-tidal CO2 partial pressure by 10%. The color Doppler imaging measurements were repeated after 2 to 4 weeks of treatment with 2 mg oral nilvadipine, and comparisons were made between the effects of the two treatments. Both CO2 inhalation and nilvadipine treatment significantly reduced the resistance index in the central retinal artery, nasal short posterior ciliary artery, and temporal short posterior ciliary artery. There was a significant correlation between the effects of the two treatments on the difference in the resistance indexes of the ophthalmic artery and central retinal artery, but not on those of the nasal or temporal short posterior ciliary artery. Both CO2 inhalation and oral nilvadipine significantly reduce the resistance index measured by color Doppler imaging in orbital vessels. The effect of oral nilvadipine might be predicted by CO2 inhalation in patients with normal-tension glaucoma.