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Fetal growth restriction
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Daniel L. Jackson, M. Y. Divon, Hung N. Winn
The ability to detect FGR with Doppler velocimetry varies considerably (Table 9). Overall, the odds ratios demonstrate a significantly increased likelihood of delivering an FGR newborn once the Doppler study is abnormal. These studies are hampered by the absence of standard definitions for both FGR and abnormal velocity waveforms. In addition, most studies have preferentially evaluated high-risk populations with an abnormally high incidence of FGR. Furthermore, the positive predictive value of abnormal Doppler velocimetry is influenced by the prevalence of FGR in the population. The prevalence is in turn affected by whether FGR is defined by population-based or customized criteria. Nonetheless, Doppler ultrasound of the UA remains a mainstay of evaluation of the fetus with FGR, and abnormal values are associated with adverse fetal outcomes (72–75).
Cardiac conditions
Published in Judy Bothamley, Maureen Boyle, Medical Conditions Affecting Pregnancy and Childbirth, 2020
A 22–24 week uterine artery Doppler (via transvaginal ultrasound) to screen for potential uteroplacental insufficiency20 may be used. Umbilical artery Doppler velocimetry is known to reflect placental function21, and this may be undertaken regularly throughout pregnancy to assess fetal well-being and underpin the timing of delivery20. Fetal echocardiography (transvaginal or transabdominal imaging studies from late in the first trimester to beyond the second trimester) by a fetal cardiologist is the normal diagnostic tool used. This may provide information for the mother (who may consider termination) or enable management plans to be made for the delivery to be at the best time and place and with relevant professionals available for a compromised baby. An early fetal echocardiography (14–16 weeks) is recommended, but many conditions may be missed at this early stage, and it is more commonly done – or repeated – at 18–22 weeks18. A detailed anomaly scan by a fetal medicine specialist should also be carried out, as there is a high frequency of extracardiac abnormalities, as well as karyotype abnormalities associated with congenital heart disease. Ongoing assessment may be necessary as some cardiac anomalies progress during pregnancy18.
The cardiac system: Physiology and principles of care
Published in Judy Bothamley, Maureen Boyle, Medical Conditions Affecting Pregnancy and Childbirth, 2020
As well as ultrasound growth studies, fetal assessment may include a specific Doppler examination of fetal pulmonary veins (Harman and Baschat, 2003) as well as the more usual umbilical arteries. A 20-week uterine artery Doppler (via transvaginal ultrasound) to screen for uteroplacental insufficiency (Papageorghiou, et al., 2001) may be used. Umbilical artery Doppler velocimetry is known to be associated with placental function (Madazli, et al., 2003) and this should be undertaken regularly throughout pregnancy to assess fetal well-being and underpin the timing of delivery (Yu and Teoh, 2006).
Discordant pH between two umbilical cord arteries at delivery for a foetus with undetected blood flow at a unilateral umbilical artery
Published in Journal of Obstetrics and Gynaecology, 2022
Shinsuke Tokoro, Shunichiro Tsuji, Daisuke Katsura, Tsukuru Amano, Takashi Murakami
In the present case, the blood flow of the unilateral umbilical cord artery was undetectable on Doppler velocimetry. First, we suspected umbilical cord artery thrombosis, which is associated with foetal growth restriction, intrauterine foetal death and other adverse perinatal outcomes (Devlieger et al. 1983; Heifetz 1988; Cook 1995). The risk factors for this are reported to include such factors as an excessively long (>70 cm) or short (<30 cm) umbilical cord, an excessively twisted umbilical cord, and the presence of knots in umbilical cords (Benirschke 1994; Redline 2004). Although gross findings, such as a short (30 cm) and excessively twisted cord, corresponded to the risk factors, thrombosis was not detected histologically. Interestingly, the measured pH values of the two umbilical arteries were quite different; the pH value of the normal sample was 7.295, while that of the viscous sample was 7.058. The difference in pH value of 0.237 was considered significant, given the accuracy of the measuring apparatus, where 90% of the absolute measuring errors are under 0.013.
Optical Coherence Tomography Angiography and Structural Analyses of the Pale Optic Discs: Is It Possible to Differentiate the Cause?
Published in Current Eye Research, 2021
Kaveh Abri Aghdam, Ali Aghajani, Marjan Razi-Khosroshahi, Mostafa Soltan Sanjari, Samira Chaibakhsh, Khalil Ghasemi Falavarjani
Analysis of the optic nerve head (ONH) microvasculature and structure to find characteristic features of different types of chronic optic neuropathies has been the concern of many investigators. Fundus fluorescein and indocyanine green angiography provide little data in differentiating the cause of optic atrophy and their application is limited due to their invasive nature, compromised qualitative information, and lack of reliable qualitative data in this regard.1,2 Laser Doppler velocimetry and laser Doppler flowmetry have been used for the evaluation of disturbances in the ONH blood flow with limited clinical applications.3 The most common imaging modality that is used to evaluate the ONH is optical coherence tomography (OCT) that provides non-invasive, fast, and precise images of the ONH.4,5 Several previous studies have shown the clinical utility of OCT measurements in different optic disc measurements.6–10
How to measure retinal microperfusion in patients with arterial hypertension
Published in Blood Pressure, 2021
Urszula Szulc, Edyta Dąbrowska, Janusz Pieczyński, Paweł Białkowski, Krzysztof Narkiewicz, Roland E. Schmieder, Joanna Harazny
Laser Doppler velocimetry and flowmetry were the first methods based on Doppler effect, which describes the relationship between the shift of frequency and relative velocity between the sender and the receiver as proportional [35]. Laser Doppler velocimetry (LDV) allowed only for the measure of absolute RBC velocity in retinal microcirculation [36] and was only suitable for estimation of retinal blood flow at one point or for measurement of its fluctuation in time caused by stimulation or pulsatory haemodynamics [37]. Laser Doppler Flowmetry (LDF), thanks to comparison between signal reflected by blood cells and by vessel walls [30], enabled relative average velocity, number and flux of RBCs in a tissue to be measured (Figure 2) [38,39]. However, the high heterogeneity of retinal vasculature and inability to re-examine the same point of the retina resulted in a limitation of application of this technology to microperfusion studies only in the human choroid tissue below macula [40].