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 Table of Contents  
ORIGINAL ARTICLE
Year : 2019  |  Volume : 32  |  Issue : 4  |  Page : 1350-1354

Three-dimensional sonographic assessment of placental volume and vascularization in pregnancies complicated by hypertensive disorders


1 Department of Obstetrics and Gynecology, Faculty of Medicine, Menoufia University, Menoufia, Egypt
2 Department of Obstetrics and Gynecology, Shebin El-Kom Teaching Hospital, Menoufia, Egypt

Date of Submission25-Jul-2018
Date of Decision19-Sep-2018
Date of Acceptance23-Sep-2018
Date of Web Publication31-Dec-2019

Correspondence Address:
Hamed H E. Yassin
Gamal Abd El Nasr Street, Shebeen El Kom, Menoufia
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/mmj.mmj_233_18

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  Abstract 

Objective
The aim was to compare placental volumes (PVs) and vascularization between normotensive pregnant women and women with hypertensive disorders using three-dimensional sonography.
Background
Hypertensive disorders in pregnancy are responsible for substantial maternal and fetal morbidity and mortality.
Materials and methods
This study was conducted at the Outpatient Clinic and Obstetric Departments of Shebin El Kom Teaching Hospital from February 2017 to January 2018. This study included 60 pregnant women, among which 20 were with normal blood pressure which served as the control group (group 1) and 20 were having chronic hypertension (group 2), and 20 with mild preeclampsia (group 3). Full history taking, physical examination, and laboratory investigation were done. Each patient from each group underwent three-dimensional ultrasound examination of the placenta for PV and placental vascular indices.
Results
There was significant statistical difference between three groups as regards PV to fetal weight ratio, with significant statistical differences between normotensive and chronic hypertensive groups (P = 0.016) and with significant statistical differences between normotensive and mild preeclamptic groups (P = 0.002). As regards placental vascular indices, there was high significant statistical differences between the three study groups (P = 0.001) as regards placental vascularization index with significant statistical differences between the three studies groups as regards placental vascular flow index (P = 0.03), But, there was no significant statistical difference between the tree groups as regards placental flow index (P = 143).
Conclusion
Pregnancies complicated by hypertensive disorders are associated with reduced placental vascularity but not with reduced PVs.

Keywords: hypertension, placenta, preeclampsia, pregnancy, three-dimensional


How to cite this article:
Soliman EA, Emarah MA, E. Shaheen AE, E. Yassin HH. Three-dimensional sonographic assessment of placental volume and vascularization in pregnancies complicated by hypertensive disorders. Menoufia Med J 2019;32:1350-4

How to cite this URL:
Soliman EA, Emarah MA, E. Shaheen AE, E. Yassin HH. Three-dimensional sonographic assessment of placental volume and vascularization in pregnancies complicated by hypertensive disorders. Menoufia Med J [serial online] 2019 [cited 2020 Apr 4];32:1350-4. Available from: http://www.mmj.eg.net/text.asp?2019/32/4/1350/274241




  Introduction Top


Hypertensive disorders in pregnancy are responsible for substantial maternal and fetal morbidity and mortality [1]. Among hypertensive disorders, preeclampsia has proven difficult to predict. Preeclampsia is a systemic syndrome that is typically characterized by new-onset hypertension and proteinuria in pregnancy (with proteinuria defined as the urinary excretion of ≥300 mg of protein in 24 h) [2]. Multiple tests have been proposed such as screening tests for preeclampsia, including analysis of maternal serum biochemical markers and sonographic parameters [3]. Placental factors that have been studied for their predictive potential for PE include A disintegrin and metalloproteinase 12 (ADAM12), free β-subunit of human chorionic gonadotropin, inhibin A, activin A, placental protein 13, placental growth factor, and pregnancy-associated plasma protein-A, which was found invasive and have a low sensitivity preventing its use alone [4]. Doppler ultrasound studies of the uteroplacental circulation in the second trimester have demonstrated that increased impedance to flow in these vessels is associated with an increased risk for subsequent development of preeclampsia and fetal growth restriction [5]. To date, the results have been conflicting. With regard to the use of sonography, various parameters have been proposed for screening, including Doppler evaluation of the uterine arteries and three-dimensional (3D) placental volumes (PVs) [6]. Although an ideal screening test detects disease as early as possible, to be effective, it must identify a clear cut point at which therapy is demonstrably beneficial. Performed too soon, a screening test may be ineffective. In the case of the above sonographic measurements, it is not clear whether assessment in the first trimester is optimally timed [7]. To date, there is no unequivocally proven intervention available that is started in the first trimester. Additional factors must be considered [8]. The aim of this study was to compare PVs and vascularization between normotensive pregnant women and women with hypertensive disorders using 3D power Doppler sonography.


  Materials and Methods Top


This study had been conducted at the Outpatient Clinic and Obstetric Departments of Shebin El-Kom Teaching Hospital from February 2017 to January 2018, after obtaining an approval from the Hospital Local Medical Ethics Committee.

The sample size was calculated by using PASS version 11 (NCSS statistical software, LLC Kaysville, Utah 84037, USA), accordingly at an α error of 0.05 and study power of 80%, a total sample size of 60 was required to detect this statistic of significant difference, 20 women in each group; the study included 60 pregnant women, among which 20 were normotensive as the control group (group 1) and 20 were having chronic hypertension (group 2), and 20 with mild preeclampsia (group 3). Inclusion criteria: age between 22 and 45 years, single viable intrauterine pregnancy, gestational age 28–40 weeks. Exclusion criteria: patients with any additional comorbidity including maternal diseases, smoking, drug use, and known fetal congenital malformations. An informed written consent was obtained from all studied patients. Obstetric history, complete general and obstetric examination, and full laboratory investigations were done. Each patient from each group underwent a 3D ultrasound examination of the placenta, and the following data were collected: the PV was obtained and measured according to the technique described. The longest view of the placenta was identified with a two-dimensional (2D) sonography, and the volume box was adjusted to scan the entire placenta. After the entire volume was scanned, the three orthogonal sonographic sections were analyzed and stored on a removable disk. The placenta was carefully identified in three orthogonal multiplanar images. The longest view of the placenta on the A-plane of the three orthogonal sonographic sections was chosen as the reference image. The volume was then measured by rotational technique with 3D Virtual Organ Computer-Aided Analysis (VOCAL) software (sonoview; GE Healthcare, Chicago, Illinois, United States), which consists of outlining the contour of the placenta repeatedly after rotating its image 6 times by 30°, with careful attention to exclude decidua and maternal vessels. After a complete rotation, the PV was automatically calculated by the software. Since PVs vary throughout pregnancy, the observed values were compared with the expected values at the gestational age at which each participant will be evaluated [9]. The placental vascular indices: were analyzed by 3D power Doppler sonography according to the method described by De paula et al. [10] using preestablished power Doppler settings (angio mode, cent; smooth, 4/5; frequency, low; quality, 16; density, 6; enhance, 16; balance, GO150; filter, 2; actual power, 2 dB; and pulse repetition frequency, 0.9) in all patients, independent of the gestational age., Power Doppler sonography was applied to obtain images of placental vasculature. The PV was acquired as described with VOCAL software with an imaging rotation of 30°. After estimation of the PV, a 3D power Doppler histogram was used to determine the vascular indices from computer algorithms. The placental vascular indices were plotted in nomograms previously reported by De paula et al. Based on their work, placental vascular indices do not vary during pregnancy; therefore, these indices were not adjusted for gestational age. The placental vascular indices were: (a) vascularization index (VI), which provides an indication of how many vessels can be detected within the placenta (vascularity); the VI is a measurement of the color voxel-to-total voxel ratio, that is, the percentage of color (vessels) within the total volume of interest (placenta); (b) flow index (FI), which provides an estimation of placental blood flow by indirect measurement of the number of blood cells that are being transported at the time of the 3D sweep; the amplitude value of the color signal is represented by the weighted color voxel (on a scale of 0–100)-to-total color voxel ratio; (c) vascularization flow index (VFI), which refers to the weighted color voxel-to-total voxel ratio; the VFI is an index of both vascularity and blood flow. For each patient, the average of two measurements of the placental vascular indices was used for the final analysis.

Statistical analysis

Results were collected, tabulated, and statistically analyzed by an IBM compatible personal computer with IBM SPSS statistics for windows, version 20.0; IBM Corp., Armonk, New York, USA). Quantitative data were expressed as mean ± SD while qualitative data were expressed as numbers and percentages (%). Student's test was used to test the significance of difference for quantitative variables and χ2 was used to test the significance of difference for qualitative variables which were less than five. A probability value P less than 0.05 was considered statistically significant. Data were analyzed and are appropriately presented in tables.


  Results Top


There were no significant statistical differences between the studied groups (P > 0.05) as regards maternal age, parity, gestational age at sonography, and the fetal weight at sonography [Table 1]. The mean of PV at sonography of the studied group was 360.8 ± 70.2 cm 3. There were no significant statistical differences between the studied groups (P > 0.05). The mean of PV to fetal weight ratio of groups 1, 2, and 3 was 0.1347 ± 0.1590, 0.1257 ± 0.01, and 0.1408 ± 0.017, respectively, with significant statistical differences between normotensive and chronic hypertensive groups (P1= 0.016) and with significant statistical differences between normotensive and mild preeclamptic groups (P2= 0.002) [Table 2]. The mean of observed to expect ratio of total studied group was 0.9732 ± 0.127 with nonsignificant statistical differences between the three study groups (P > 0.05). The mean of placental VI of total studied group was 11.62 ± 5.95 with highly significant statistical differences between the three studied groups (P = 0.001) with significant statistical differences between normotensive and chronic hypertensive groups (P < 0.05), with significant statistical differences between normotensive and mild preeclamptic groups (P2= 0.006), and nonsignificant statistical differences between chronic hypertensive and mild preeclamptic groups (P = 0.374). The mean of placental flow index (FI) of the total studied group was 43.2 ± 2.89 and the mean of groups 1, 2, and 3 was 43.6 ± 3.4, 43.83 ± 2.5, and 42.23 ± 2.4, respectively, with nonsignificant statistical differences between the three study groups (P = 0.143). The mean of placental VFI of total studied group was 5.84 ± 3.68 and the mean of groups 1, 2, and 3 was 7.66 ± 4.14, 5.29 ± 3.69, and 4.58 ± 2.40, respectively, with significant statistical differences between the three study groups (P = 0.01), with significant statistical differences between normotensive and chronic hypertensive groups (P < 0.05), with significant statistical differences between normotensive and mild preeclamptic groups (P5= 0.007) and nonsignificant statistical differences between chronic hypertensive and mild preeclamptic groups (P = 0.526) [Table 3]. In the normotensive group there was nonsiginificant statistical corerelation between gestational age and placental FI and placental VFI. There was significant positive correlation between GA and PV and placental VI (r = 0.593, 0.535; P = 0.006, P = 0.01), respectively. In the chronic hypertensive group there was nonsiginificant statistical corerelation between gestational age and placental VI and placental FI. There was significant positive correlation between GA and PV and placental VFI (r = 0.459, 0.56; P = 0.04, and P = 0.01), respectively. In the mild preeclamptic group there was nonsiginificant statistical corerelation between gestational age and placental VI, placental FI and placental VFI. there was significant positive correlation between GA and PV (r = 0.593; P = 0.006) [Table 4].
Table 1: Comparison of studied groups regarding personal data (n=60)

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Table 2: Comparison of studied groups regarding placenta volume and placental volume to fetal weight ratio (n=60)

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Table 3: Comparison of studied groups regarding placenta vascular indices (n=60)

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Table 4: Correlations between gestational age, placental volume, and vascularization indices

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  Discussion Top


Our results suggest that hypertensive disorders in pregnancy are not associated with lower PVs than those in healthy pregnancies. There is a tendency for PVs to be lower in pregnancies complicated by superimposed preeclampsia, a fact that can be confirmed by assessing the PV to fetal estimated weight ratio. Conversely, when compared with normotensive pregnant women, women with hypertensive disorders have significantly reduced vascularization indices. This finding is most pronounced in patients with superimposed preeclampsia. Our result is in agreement with Pimenta et al. [7]. PVs and vascularity were evaluated by 3D sonographic, 3D power Doppler histographic, and 2D color Doppler studies. Pregnant women were classified as normotensive or hypertensive and stratified by the nature of their hypertensive disorders. The following variables were evaluated: observed-to-expected PV ratio, PV-to-estimated fetal weight ratio, and placental vascular indices. In all, 66 healthy pregnant women and 62 pregnant women with hypertensive disorders were evaluated (matched by maternal age, gestational age at sonography, and parity). PVs were not reduced in pregnancy in women with hypertensive/disorders (P > 0.05). Conversely, reduced placental vascularization indices (VI and VFI) were observed in pregnancies complicated by hypertensive disorders (P < 0.01; <0.01). Our result is also in agreement with Yan et al. [11]. Pregnant women underwent 3D PD and VI, FI, and VFI were obtained. The placental VI and VFI were significantly lower in the hypertensive group than in the normotensive women (P < 0.001 and 0.014, respectively) but as regards placental FI there was no significant statistical difference between both groups. Suranyi et al. [12] had a study done on 226 pregnancies. The result of this study is in agreement with our study as regards placental vascular indices. This study demonstrated that there was significant statistical difference as regards placental VI (P = 0.001) and VFI (P = 0.002) but not the placental FI (P = 0.141). While our study demonstrated that there was significant statistical difference as regards placental VI (P = 0.001) and VFI (P = 0.001) but not placental FI (P = 0.143). The result of this study is not in agreement with our study as regards PV. The result of this study demonstrated that PV was significantly smaller (P < 0.001) in all three pathological groups than in normal pregnancies at the time of delivery.


  Conclusion Top


  1. Pregnancies complicated by hypertensive disorders are associated with reduced placental vascularity and are not associated with reduced PVs
  2. Larger multicenter studies should be conducted in the first trimester to determine whether this decreased vascularization has a causative effect or is consequential to hypertensive disorders in pregnancy.


Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

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Hutcheon JA, Lisonkova S, Joseph KS. Epidemiology of preeclampsia and the other hypertensive disorders of pregnancy. Best Pract Res Clin Obstet Gynecol 2011; 25:391–403.  Back to cited text no. 2
    
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Neil O, Wright D, Syngelaki A, Akolekar R, Wright A, Poon LC, et al. Competing risks model in screening for preeclampsia by maternal factors and biomarkers at 11-13 weeks' gestation. Am J Obstet Gynecol 2016; 214:103–111.  Back to cited text no. 3
    
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Sylwia K, Wortelboer KJ, van Rijn BB, Franx A, Visser GH, Schielen PC. Evaluation of 7 serum biomarkers and uterine artery Doppler ultrasound for first-trimester prediction of preeclampsia: a systematic review. Obstet Gynecol Surv 2011; 66:225–239.  Back to cited text no. 4
    
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Schuchter K, Metzenbauer M, Hafner E, Philip K. Uterine artery Doppler and placental volume in the first trimester in the prediction of pregnancy complications. Ultrasound Obstet Gynecol 2013; 18:590–592.  Back to cited text no. 5
    
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Pimenta EJ, Silva de Paula c, Fox AK, R Francisco, Rodrigo R. Three-dimensional sonographic assessment of placental volume and vascularization in pregnancies complicated by hypertensive disorders – the American Institute of Ultrasound Medicine. J Ultrasound Med 2014; 33:483–491.  Back to cited text no. 7
    
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Brown DW, Dueker N, Jamieson DJ, Cole JW, Wozniak MA, Stern BJ, et al. Preeclampsia and the risk of Ischemic stroke among young women. Results from the stroke prevention in young women study. Stroke 2006; 37:1055–1059.  Back to cited text no. 8
    
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Cunningham FG, Gant NE, Leveno KJ, Steven LB, John CH, larry CG, et al. Hypertensive disorders in pregnancy. In: Gary CF. Williams obstetrics. 24nd ed. New York: Mcgraw-Hill; 2014. 761–808.  Back to cited text no. 9
    
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De Paula CF, Ruano R, Camppos JA, Zugaaib M. Quantitative analysis of placental vasculature by three-dimensional power Doppler ultrasonography in normal pregnancies from 12 to 40 weeks' gestation. Placenta 2009; 30:142–148.  Back to cited text no. 10
    
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Yan T, Zhang T, Han Z. placental vascularization alterations in hypertensive disorders complicating pregnancy (HDCP) and small for gestational age with HDCP using three dimensional power Doppler in a prospective case control study. BMC Pregnancy Childbirth 2015; 15:240.  Back to cited text no. 11
    
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Suranyi A, Altorjay A, Kaiser L, Nyari T, Nemeth G. Evaluation of placental vascularization by three-dimensional ultrasound examination in second and third trimester of pregnancies complicated by chronic hypertension, gestational hypertension or pre-eclampsia. Pregnancy Hypertens 2017; 8:51–59.  Back to cited text no. 12
    



 
 
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  [Table 1], [Table 2], [Table 3], [Table 4]



 

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