Ophthalmic artery Doppler velocimetry in healthy pregnancy

Ophthalmic artery Doppler in the complementary diagnosis of preeclampsia: a systematic review and meta-analysis

OBJECTIVE

To evaluate the accuracy of different parameters of the ophthalmic artery Doppler (OAD) in the complementary diagnosis of preeclampsia (PE).

METHODS

This meta-analysis adhered to the PRISMA guidelines. To investigate the mean difference in OAD values, peak systolic velocity (PSV), end-diastolic velocity (EDV), second systolic velocity peak (P2), resistance index (RI), pulsatility index (PI), and peak ratio (PR), between PE cases (overall and according to severity) and controls, random-effects meta-analyses were conducted for each Doppler parameter, with overall PE and mild and severe PE subgroups. Diagnostic performance and heterogeneity were evaluated with summary receiver operating characteristic (sROC) curves and 95% confidence intervals obtained with bivariate models.

RESULTS

Eight studies stratified the results into mild and severe or late and early PE, involving 1,425 pregnant women. PR and P2 had better diagnostic performance than the other indexes, with the PR of AUsROC at 0.885, the sensitivity of 84%, and specificity of 92%, with a low false-positive rate of 0.08 and the P2 with AUsROC of 0.926, the sensitivity of 85% and specificity of 88%. RI, PI, and EDV showed good performance and consistency across studies but lower AUsROC values of 0.833, 0.794, and 0.772, respectively.

CONCLUSION

Ophthalmic artery Doppler is a complementary tool with good performance for the diagnosis of overall and severe preeclampsia, with high and best sensitivity and specificity when using PR and P2 parameters.

Ophthalmic artery Doppler for pre-eclampsia prediction at the first trimester: a Bayesian survival-time model

OBJECTIVE

To develop a Bayesian survival-time model for the prediction of pre-eclampsia (PE) at the first trimester using a combination of established biomarkers including maternal characteristics and history, mean arterial pressure (MAP), uterine artery Doppler pulsatility index (UtA-PI), and Placental Growth Factor (PlGF)) with an ophthalmic artery Doppler peak ratio (PR) analysis.

METHODS

The receiving operator curve (ROC) analysis was used to determine the area under the curve (AUC), detection rate (DR), and positive screening cut-off value of the model in predicting the occurrence of early-onset PE (< 34 weeks' gestation) and preterm PE (< 37 weeks' gestation).

RESULTS

Of the 946 eligible participants, 71 (7.49%) subjects were affected by PE. The incidences of early-onset and preterm PE were 1% and 2.2%, respectively. At a 10% false-positive rate, using the high-risk cut-off 1:49, with AUC 0.981 and 95%CI 0.965-0.998, this model had an 100% of DR in predicting early-onset PE. The DR of this model in predicting preterm PE is 71% when using 1:13 as the cut-off, with AUC 0.919 and 95%CI 0.875-0.963.

CONCLUSION

Combination ophthalmic artery Doppler PR with the previously established biomarkers could improve the accuracy of early and preterm PE prediction at the first trimester screening.

Alternatives of Risk Prediction Models for Preeclampsia in a Low Middle-Income Setting

Abstract Objectives:  To  develop prediction models for the first-trimester prediction of PE (PE) using the established biomarkers including maternal characteristics and history, mean arterial pressure (MAP), uterine artery Doppler pulsatility index (UtA-PI ), and Placental Growth Factor (PlGF)) in combination with Ophthalmic artery Doppler peak ratio (PR). Methods:  This was a  prospective observational study in women attending a first-trimester screening at 11-14 weeks’  gestation. Maternal characteristics and history, measurement of MAP, ultrasound examination for UtA-PI measurement, maternal ophthalmic PR Doppler measurement, and serum  PlGF collection were performed during the visit. Logistic regression  analysis was used to determine if the maternal factor had a significant contribution in predicting PE. The Receiving Operator Curve (ROC) analysis was used to determine the area under the curve  (AUC), positive predictive value  (PPV), negative prefictive value (NPV) and positive screening cut-off in predicting the occurrence of PE at any gestational age.   Results: Of the 946 eligible participants, 71 (7,49%) subjects were affected by PE. Based on the ROC curves, optimal high-risk cutoff value for prediction of preeclampsia at any gestational age for model 2 (primary care model) in this Indonesia study population were 63% with the sensitivity and specificity of 71.8% and 71.2%, respectively. Both sensitivity and specificity for model 3 (complete model) were 70.4% and 74.9%, respectively for the cutoff value 58%. The area under the curve of model 2, model 3 was 0.7651 (95% CI: 0.7023-0.8279)) and 0.7911 (95% CI: 0.7312-0.8511), respectively, for predicting PE. In addition, PPV and NPV for model 2 were 16.8% and 96.9%, respectively. PPV and NPV for model 3 were 18.55 and 96.9%, respectively.   Conclusion: The prediction models of preeclampsia vary depending upon healthcare resource. Complete model is clinically superior to primary care model but it is not statistically significant.  Prognostic models should be easy to use, informative and low cost with great potential to improve maternal and neonatal health in Low Middle Income Country settings. 

Performance of ophthalmic artery Doppler velocimetry in the complementary diagnosis of preeclampsia

OBJECTIVES

To calculate the accuracy (A) and establish the best cutoff value for ophthalmic artery (OA) Doppler velocimetry indexes in patients diagnosed with preeclampsia (PE), compared with healthy pregnant women.

METHODS

This prospective experimental study enrolled 268 women: 133 with PE and 135 healthy pregnant women. All patients were evaluated by OA Doppler sonography, bilaterally, to assess their pulsatility index (PI), resistance index (RI), peak systolic velocity (PVS), second peak systolic velocity (P2), end-diastolic velocity (EDV), and peak ratio (PR). Means were compared using Student's T-test. Receiver Operating Characteristics (ROC) curve was used to establish the cutoff value and estimate the sensitivity (S), specificity (Sp), accuracy (A) of all variables, and a significance of 95% was adopted.

RESULTS

ROC curve analysis showed that P2 and PR were superior to the other parameters for PE diagnosis. We tested two cutoff values: (1) using PR ≥0.70, obtained A: 88.72%, S: 81.95%, and Sp: 95.48% and (2) using PR ≥0.75, and A: 86.24%, S: 74.43%, and Sp: 99.24%. By adopting P2 ≥ 21.5 cm/s, we obtained A: 87.59%, S: 84.96%, and Sp: 90.22% and when the cutoff point was P2 ≥ 22 cm/s, there was a slight decrease in A to 86.46% and S to 81.20%, with Sp: 91.89.3%.

CONCLUSION

Ophthalmic artery Doppler demonstrated to be an effective and high-performance imaging method for the diagnosis of PE and the indexes P2 and PR demonstrated superior accuracy to the other Doppler parameters assessed. Higher performance occurred when the cutoff values with greater specificity were adopted, PR ≥ 0.75 and P2 ≥ 22 cm/s, considering that the proposed OA Doppler is to be a complementary method for preeclampsia.

Doppler Velocimetry of the Ophthalmic Artery Behavior in Twin Pregnancy

Our main objective was to evaluate the ophthalmic artery Doppler behavior in twin pregnancies and compare with singleton pregnancies. We studied 64 healthy twin pregnant women between 12 to 38 weeks of gestation. Resistance index (RI), pulsatility index (PI), and peak ratio (PR) were determined. The control group consisted of 289 singletons. Linear regression analysis was performed to evaluate the association between gestational age and the ophthalmic indexes. Student t test was used to compare the means and standard deviation of the Doppler indexes. There was a decrease in RI and PI and an increase in PR with advancing gestational age (ρ < 0.0001, 0.0052, and 0.0033). The means ± SDs for RI, PI, and PR were 0.77 ± 0.07, 1.79 ± 0.46, and 0.53 ± 0.12, in women with twin pregnancies and 0.75 ± 0.05, 1.88 ± 0.43, and 0.52 ± 0.10 in singletons. No significant difference was found between the PI and PR values, but significant difference was found in the RI values between the groups (P = 0.0332). We concluded that there are no significant differences in ophthalmic artery behavior in twins and the same reference values established in singleton pregnancies can be applied for PI and PR indexes in the evaluation of twin pregnancies. These indexes were the best to evaluate twin pregnancies.

Doppler Indices of the Ophthalmic Artery in Pregnant Women With Pregestational Diabetes Mellitus With and Without Retinopathy

OBJECTIVES

To evaluate ophthalmic Doppler velocimetry patterns in pregnant women with pregestational diabetes mellitus with and without retinopathy in comparison to pregnant women without gestational intercurrences.

METHODS

This cross-sectional observational study analyzed Doppler indices of the ophthalmic arteries, including the resistive index (RI), pulsatility index, peak systolic velocity, second peak systolic velocity, peak ratio, and end-diastolic velocity (EDV), in 3 groups of pregnant women: diabetic with retinopathy (n = 12); diabetic without retinopathy (n = 85); and nondiabetic controls (n = 122). The Kruskal-Wallis test was used for the statistical analysis with a probability of 95%.

RESULTS

The mean gestational ages ± SDs of pregnant women with and without retinopathy and nondiabetic controls were 29.1 ± 2.2, 29.7 ± 2.7, and 31 ± 1.0 weeks, respectively, with no significant differences between the groups (P > .099). The mean RI in the group with retinopathy was significantly higher (P = .030) than in the control group, but it did not significantly differ compared to the group without retinopathy (P = .204). The RI in the control group did not differ from that in the group without retinopathy (P = .079). The EDV was significantly lower in the group with retinopathy (P = .015) in relation to the control group, but there were no differences compared to the group without retinopathy (P = .217).

CONCLUSIONS

Pregnant women with pregestational diabetes mellitus and retinopathy had increased vascular impedance in the ophthalmic artery together with a reduction in the EDV, which was probably related to ischemia, thrombosis, and neovascularization of retinal vessels.

Effects of age on the peak ratio of ophthalmic artery Doppler

This study aimed to investigate the effects of age on the peak ratio (PR) of ophthalmic artery (OA) Doppler.The initial peak velocity (P1), second peak velocity (P2) and PR of OA were detected by color Doppler ultrasonography in 147 healthy subjects. All of the subjects were divided into 6 groups (G1-G6) according to the age. (G1, 20-29 years; G2, 30-39 years; G3, 40-49 years; G4, 50-59 years; G5, 60-69 years; and G6, 70 years or older). The blood pressure and heart rate were also examined before ultrasonography. The influences of age, blood pressure and heart rate on the P1, P2, and PR were further evaluated.There were significant differences in the P2 and PR among different age groups except for P1. There were no significant differences in the P2 and PR between the first 2 groups, neither among the latter 4 groups. Nevertheless, P2 and PR in the first 2 groups were significantly different from those in the latter 4 groups. In addition, both P2 and PR (not P1) increased significantly with age, systolic and diastolic blood pressure. P1, P2 and PR were not related to heart rate. Both P2 and PR were closely related to the age. PR also had a weak relationship with systolic blood pressure.Both P2 and PR of OA Doppler increase with age. Concern should be raised when P2 and PR are used to evaluate the hemodynamic change of OA.

What Is the Role of the Maternal Ophthalmic and Cervical Internal Carotid Arteries in Predicting Maternal Adverse Outcomes in Preeclampsia?

OBJECTIVES

We aimed to investigate the efficacy of maternal ophthalmic artery (OA) and cervical internal carotid artery (CICA) in predicting adverse maternal outcomes and gestational age at birth in preeclampsia (PE).

METHODS

The study was performed at the Zeynep Kamil Women and Children's Diseases Training and Research Hospital. Measurements were made in 2 groups consisting of 50 pregnant women with PE and 50 healthy pregnant women. The peak systolic velocity (PSV), end-diastolic velocity, PI, RI, first diastolic peak velocity, systolic/diastolic (S/D) ratio, and peak ratio of the maternal OA were measured by a transorbital Doppler ultrasound (US) scan. The PSV, end-diastolic velocity, PI, RI, and S/D ratio of the CICA were measured. The differences of Doppler indices between groups with P < .05 were considered statistically significant. Cutoff values were calculated, which could be used to predict adverse maternal outcomes and gestational age at birth.

RESULTS

The RI and PI values of the OA were lower, and the first diastolic peak velocity, PSV, and peak ratio values were higher among the PE group. The RI and S/D values of the CICA were significantly lower in the PE group compared to the healthy group. The OA RI was determined to be the strongest US variable in predicting adverse maternal outcomes and gestational age at birth, with a cutoff value of 0.72, 76% sensitivity, and 76% specificity.

CONCLUSIONS

Maternal OA Doppler indices can be used as US markers to predict adverse maternal outcomes.

Optic nerve sonography and ophthalmic artery Doppler velocimetry in healthy pregnant women: an Australian cohort study

PURPOSE

Maternal ocular sonography offers a window into cerebrovascular and intracranial pressure changes in pregnancy. This study aimed to determine the Doppler velocimetric variables of the ophthalmic artery, and the mean diameter of the optic nerve sheath (ONSD), in an Australian cohort of healthy pregnant women.

METHODS

A prospective observational cohort study of healthy women with uncomplicated singleton pregnancies in the third trimester was undertaken in a tertiary maternity service. A single prenatal ultrasonographic examination was performed on all participants, with a postnatal examination performed on a subgroup with uncomplicated deliveries.

RESULTS

Fifty women were examined at a mean gestation of 35 weeks. The mean ± SD Doppler variables in the ophthalmic artery were peak systolic velocity (PSV) 41.89 ± 13.13 cm/s, second peak velocity 20.63 ± 8.97 cm/s, end diastolic velocity 9.29 ± 5.13 cm/s, pulsatility index 1.97 ± 0.53, resistive index 0.78 ± 0.07, peak ratio (second peak velocity/PSV) 0.49 ± 0.12, while the mean ONSD was 4.34 ± 0.4 mm. None of these variables had a demonstrable relationship with gestation or mean arterial pressure (MAP), nor did the sheath diameter have a relationship with any of the Doppler variables.

CONCLUSIONS

The ocular sonographic variables observed in this population are similar to those reported in other cohorts. No clear relationship could be identified in this cohort between ophthalmic artery Doppler variables and the ONSD, and between each of these variables and gestation or MAP.

Ophthalmic artery Doppler for prediction of pre-eclampsia: systematic review and meta-analysis

OBJECTIVE

To determine the accuracy of ophthalmic artery Doppler in pregnancy for the prediction of pre-eclampsia (PE).

METHODS

MEDLINE, EMBASE, CINAHL and The Cochrane Library were searched for relevant citations without language restrictions. Two reviewers independently selected studies that evaluated the accuracy of ophthalmic artery Doppler to predict the development of PE and extracted data to construct 2 × 2 tables. Individual patient data were obtained from the authors if available. A bivariate random-effects model was used for the quantitative synthesis of data. Logistic regression analysis was employed to generate receiver-operating characteristics (ROC) curves and obtain optimal cut-offs for each investigated parameter, and a bivariate analysis was employed using predetermined cut-offs to obtain sensitivity and specificity values and generate summary ROC curves.

RESULTS

A total of 87 citations matched the search criteria of which three studies, involving 1119 pregnancies, were included in the analysis. All included studies had clear description of the index and reference tests, avoidance of verification bias and adequate follow-up. Individual patient data were obtained for all three included studies. First diastolic peak velocity of ophthalmic artery Doppler at a cut-off of 23.3 cm/s showed modest sensitivity (61.0%; 95% CI, 44.2-76.1%) and specificity (73.2%; 95% CI, 66.9-78.7%) for the prediction of early-onset PE (area under the ROC curve (AUC), 0.68; 95% CI, 0.61-0.76). The first diastolic peak velocity had a much lower sensitivity (39.0%; 95% CI, 20.6-61.0%), a similar specificity (73.2%; 95% CI, 66.9-78.7%) and a lower AUC (0.58; CI, 0.52-0.65) for the prediction of late-onset PE. The pulsatility index of the ophthalmic artery did not show a clinically useful sensitivity or specificity at any cut-off for early- or late-onset PE. Peak ratio above 0.65 showed a similar diagnostic accuracy to that of the first diastolic peak velocity with an AUC of 0.67 (95% CI, 0.58-0.77) for early-onset PE and 0.57 (95% CI, 0.51-0.63) for late-onset disease.

CONCLUSIONS

Ophthalmic artery Doppler is a simple, accurate and objective technique with a standalone predictive value for the development of early-onset PE equivalent to that of uterine artery Doppler evaluation. The relationship between ophthalmic Doppler indices and PE cannot be a consequence of trophoblast invasion and may be related to maternal hemodynamic adaptation to pregnancy. The findings of this review justify efforts to elucidate the effectiveness and underlying mechanism whereby two seemingly unrelated maternal vessels can be used for the prediction of a disease considered a 'placental disorder'. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Magnesium sulfate and ophthalmic artery Doppler velocimetry in patients with severe preeclampsia: a case series

Background

In the present study, we used Doppler velocimetry in the ophthalmic artery to evaluate the hemodynamic status of the intracranial vasculature. This is the first time in the literature that indices of ophthalmic artery Doppler sonography of women with preeclampsia were evaluated before and after the use of magnesium sulfate to prevent eclampsia.

Case presentation

Indices of ophthalmic artery Doppler sonography of six women with severe preeclampsia at 27 to 33 weeks of gestational age were evaluated before and after the use of magnesium sulfate (10 minutes, 30 minutes, and 60 minutes after the magnesium sulfate loading dosage. The patients’ ages were 26 years (patient 01), 29 years (patient 02), 20 years (patient 03), 21 years (patient 04), 20 years (patient 05), and 19 years (patient 06). The ethnic group of patients 01 and 04 was white and the ethnic group of patients 02, 03, 05 and 06 was mulatto.

Conclusions

The apparent increase in resistance index and pulsatility index values, although there is no statistical significance in this series of cases, and the decrease in peak ratio values after the administration of magnesium sulfate reflect an increase in the impedance to flow in the ophthalmic artery and consequently a reduction in cerebral perfusion after the use of magnesium sulfate. This may explain how magnesium sulfate protects women with severe preeclampsia against cerebral damage and prevents acute convulsions in these patients. We believe that this case series report may have a broader clinical impact across medicine because the mechanism of how magnesium sulfate can protect patients and prevent acute convulsions is controversial.

Choroidal Thickness in Women with Uncomplicated Pregnancy: Literature Review

Pregnancy is a time when many changes occur in a woman's body. The goal of these changes is the provision of optimum conditions for the development of the foetus. Pregnancy also affects eye physiology. Well recognized physiological changes include a reduced corneal sensitivity, an increase in its central thickness and curvature, and a decrease in intraocular pressure. The association between choroidal thickness and pregnancy is not clear. Haemodynamic and hormonal changes taking place during pregnancy and the question of whether these changes are reflected by choroidal thickness are especially important. It is assumed that the choroid, which is one of the most highly vascularized tissues characterized by the highest blood flow to tissue volume ratio in the whole body, should respond by an increase in its thickness to an increase in blood flow and drop in the value of peripheral resistance. Measurement of choroidal thickness using enhanced depth imaging optical coherence tomography (EDI-OCT) in women with uncomplicated pregnancy provides important information concerning the effects of physiological changes in the eye.

Maternal ophthalmic artery Doppler velocimetry in pre-eclampsia in Southwestern Nigeria

BACKGROUND

Pre-eclampsia (PE) poses a serious challenge to maternal and fetal health in Africa. It is associated with hemodynamic changes that may affect the internal carotid/ophthalmic artery circulation with consequent neuro-ophthalmic manifestations. Ophthalmic artery Doppler (OAD) ultrasound is an important tool that can be used to detect hemodynamic changes in PE and monitor its severity. In this study, we evaluated hemodynamic changes on OAD ultrasound in the ophthalmic arteries of pre-eclamptic women and compared these with values in healthy pregnant women.

METHODS

OAD parameters, such as, peak systolic velocity, peak diastolic velocity, end diastolic velocity, pulsatility index, and peak ratio, were measured on transorbital triplex ultrasound scan with a 7-10 MHz multifrequency linear transducer in 42 consenting pre-eclamptic patients and 41 pregnant controls matched for maternal age, gestational age, and parity at the Department of Radiology, University College Hospital, Ibadan. Univariate, bivariate, and receiver operating characteristic curve data analyses were performed. P<0.05 was considered to be statistically significant.

RESULTS

Mean resistivity index, pulsatility index, and peak systolic velocity were significantly lower in pre-eclamptic patients than in the controls. Mean peak diastolic velocity, end diastolic velocity, and peak ratio were significantly higher in the pre-eclamptic group. The receiver operating characteristic curve showed that the resistivity index (sensitivity 75%, specificity 77.8%) could distinguish mild from severe PE while the peak ratio (sensitivity 90.5%, specificity 81.3%) could accurately detect PE.

CONCLUSION

OAD ultrasound can be used to monitor patients with PE for early detection of progression to severe forms before cerebral complications develop. OAD screening of patients at high risk for PE can also detect early changes of hemodynamic derangement.

First-trimester maternal ophthalmic artery Doppler analysis for prediction of pre-eclampsia

OBJECTIVE

To determine the performance of a multiparametric test comprising maternal risk factors, uterine artery Doppler and ophthalmic artery Doppler in the first trimester of pregnancy for the prediction of pre-eclampsia (PE).

METHODS

This prospective observational cohort study recruited patients in the first trimester of pregnancy. Maternal uterine artery and ophthalmic artery Doppler assessments were performed in 440 singleton pregnancies at 11-14 weeks of gestation. Additional history was obtained through participant questionnaires, and follow-up occurred to discharge postdelivery. The normotensive and pre-eclamptic groups were compared using parametric (Student's t-test) and non-parametric (Mann-Whitney U-test) tests. Univariable and multivariable logistic regression analyses were performed to determine which biophysical factors, and which of the factors among the maternal characteristics and medical and obstetric history, had a significant contribution to the prediction of PE in a multiparametric model.

RESULTS

Thirty-one (7%) patients developed PE, including nine (2%) who required delivery before 34 weeks (early PE) and 22 (5%) with late PE. There were statistically significant differences in uterine artery pulsatility index (UtA-PI) and ophthalmic artery first diastolic peak (PD1) mean values between the PE and control groups. In a multiparametric model, both UtA-PI and PD1 achieved a 67% detection rate for early PE, although when combined, the detection rate only increased to 68%.

CONCLUSIONS

The efficiency of ophthalmic artery PD1 in the first trimester as a predictive marker for the later development of PE was approximately equal to that described for uterine artery Doppler. Although these findings do not support the replacement of uterine artery Doppler analysis in multiparametric predictive models for PE, they do provide novel insights into first-trimester maternal systemic vascular changes that precede the clinical development of this condition.

Reference values of maternal ophthalmic artery doppler variables in the first trimester of normal pregnancy

BACKGROUND

The aim of this study was to establish normative data for ophthalmic artery Doppler variables in the first trimester of normal pregnancy.

METHODS

Maternal ophthalmic artery Doppler signals were recorded in 409 singleton pregnancies at 11-14 weeks' gestation, in mothers presenting consecutively for routine antenatal care. Pulsatility and resistance indices (PI, RI), peak systolic velocity (PSV), first peak diastolic velocity (PD1), and peak ratio (PR) were measured. Quartile regression was used to estimate reference ranges in the late first trimester of pregnancy.

RESULTS

Mean ± SD values for maternal ophthalmic artery Doppler parameters between 11 and 14 weeks' gestation were RI = 0.81 ± 0.12, PI = 2.06 ± 0.57, PSV = 36.41 ± 12.1, PD1 = 21.07 ± 7.62, and PR = 0.58 ± 0.11. All clinical and Doppler variables were normally distributed. PD1 values were higher in patients who smoked, and in those with diabetes or a history of pre-eclampsia. PR values were higher in patients with diabetes and chronic hypertension, and lower in the nulliparous; these values declined as gestation advanced from 11 to 14 weeks, whereas the other variables remained unchanged.

CONCLUSIONS

We provide reference values for maternal ophthalmic artery Doppler variables in the first trimester of normal pregnancy.

Power M-mode transcranial Doppler examination of the ophthalmic artery in pregnancy: standard operating procedure and review of the literature

Our aim was to describe the standard operating procedure for transcranial Doppler investigation of the ophthalmic artery in pregnancy, determine the interobserver and intraobserver variability using power M-mode technology, and review the existing literature. Accordingly, 27 healthy pregnant or immediately postpartum women were enrolled and underwent transcranial Doppler investigation of the ophthalmic artery using power M-mode technology. Good interobserver and intraobserver variability was observed for both, especially with respect to the clinically important indices. Transcranial Doppler power M-mode examination of the ophthalmic artery is easy and reproducible and holds a great deal of potential for investigation in pregnancy.

Doppler study and evidences of perfusion changes in the ophthalmic artery of pregnant smokers

OBJECTIVES

To compare the ophthalmic artery (OA) perfusion of pregnant smokers and nonsmokers by Doppler indexes. Correlate these with the interval of last cigarette, cigarettes per day, years smoking and carbon monoxide expired (COex).

METHOD

Transversal study involving 70 pregnant smokers divided into 33 pregnant who smoked until 2 h: A group (AG) and B group (BG): 37, who smoked between 2 and 24 h before test. Control group (CG) was composed of 51 pregnant nonsmokers. Doppler indexes were assessed: PSV (Peak Systolic Velocity), EDV (End Diastolic Velocity), PI (Pulsatility Index), RI (Resistance Index) and PR (Peak Ratio). Groups were compared using ANOVA, Kruskal-Wallis test, Student's t test, Mann-Whitney and Pearson's correlation coefficient, whereas p < 0.05.

RESULTS

RI and PI were higher (p < 0.01) and PSV and EDV were lower (p < 0.05) in B group compared to other groups. A group presented higher PR (p < 0.01) compared to control. AG presented years of smoking, cigarettes per day, COex greater than BG and lower interval of last cigarette than BG.

CONCLUSIONS

The OA in pregnant smokers shows a biphasic pattern of perfusion correlated with the time of consumption of the last cigarette. There are signs of vasoconstriction and hypoperfusion to tobacco exposure between 2 and 24 and hyperperfusion in A Group compared to B Group.

Changes in ophthalmic artery Doppler indices in hypertensive disorders during pregnancy

OBJECTIVES

To compare the ophthalmic artery Doppler indices observed in women with singleton pregnancies complicated by hypertension and to correlate the indices observed in hypertensive pregnant women with those observed in healthy pregnant women.

METHODS

Ophthalmic artery Doppler indices were compared between 30 women with mild preeclampsia, 30 women with severe preeclampsia, and 30 women with chronic hypertension at 20 to 40 weeks' gestation. The control group consisted of 289 normotensive pregnant women. The resistive index, pulsatility index, and peak ratio were measured in the right eye. The mean and standard deviation were calculated for each group. Analysis of variance and the Tukey method were used to compare the means of the Doppler indices between groups. Receiver operating characteristic curves were used to determine the predictive power of the Doppler indices for identification of women with severe preeclampsia. P < .05 was considered statistically significant.

RESULTS

Significant differences were found between the resistive index, pulsatility index, and peak ratio in women with severe preeclampsia compared to the other groups. The means ± SDs for the resistive index, pulsatility index, and pulse ratio in women with severe preeclampsia were 0.63 ± 0.09, 1.13 ± 0.31, and 0.89 ± 0.12, respectively. The optimal cutoff values for the resistive index, pulsatility index and the peak ratio for identification of women with severe preeclampsia were determined by the receiver operating characteristic curves to be 0.657, 1.318, and 0.784.

CONCLUSIONS

Doppler imaging of the ophthalmic artery showed central overperfusion among pregnant women with severe preeclampsia. The peak ratio was the best index for discriminating between severe and mild preeclampsia or chronic hypertension.

Doppler velocimetry of the ophthalmic artery: reproducibility of blood flow velocity measurements

OBJECTIVES

The aim of this study was to investigate the interobserver reliability for measuring ophthalmic artery Doppler indices.

METHODS

Healthy women (n = 30) were evaluated. The resistive index, pulsatility index, and peak ratio were determined by two independent observers who were blind to each other. A paired t test was used for the comparison of paired samples in the cases of replication between observers. Pearson product-moment correlation was used to study the relationship between the samples. The Bland-Altman graphic approach was used to investigate the agreement between observers.

RESULTS

No significant differences were found between the values obtained by the two independent observers for the resistive index and pulsatility index. The difference observed between the values obtained by the observers for the peak ratio was 0.02.

CONCLUSIONS

Doppler velocimetry is a reproducible technique for evaluation of the resistive index and pulsatility index. For analysis of the peak ratio, an interval of ±0.02 should be considered for the measurement.

Doppler velocimetry of the ophthalmic artery in normal pregnancy: reference values

OBJECTIVE

This study aimed at analyzing the correlation between ophthalmic Doppler indices and gestational age (GA) in healthy patients with singleton pregnancies. Intraobserver reproducibility and right-to-left eye correlation were also evaluated.

METHODS

Healthy pregnant women (n = 289) at 20 to 40 weeks' GA were evaluated. The resistive index (RI), pulsatility index (PI), and peak ratio (PR) were determined by 2 measurements in each eye. Comparisons were performed first between the 2 measurements in each eye and later between the right and left eyes. Spearman rank correlation was used to analyze the relationship of the RI, PI, and PR with GA. Linear regression analysis was also performed.

RESULTS

No significant differences were found between the values obtained for the first and the second measurements in each eye and those for the RI, PI, and PR in the right and left eyes. There was a significant decrease in RI and PI values with advancing GA, however (rho = -0.264 and -0.1192, respectively), with low R(2) values for both. Thus, only a small proportion of the variations observed in the RI and PI was associated with changes in GA. No significant difference was found between the PR values with regard to GA intervals.

CONCLUSIONS

Doppler velocimetry is a reproducible technique for evaluation of the RI, PI, and PR in the ophthalmic artery. Unilateral analysis of these indices can be used. Linear regression analysis indicated that other factors were associated with a decrease in the RI and PI values with advancing GA. No significant change was observed in the PR values throughout normal pregnancy.