Original Paper Fetal Diagn Ther 2014;36:299–304 DOI: 10.1159/000361021
Received: December 30, 2013 Accepted after revision: February 28, 2014 Published online: August 1, 2014
Uterine Artery Pulsatility Index Assessment at 11–13+6 Weeks’ Gestation Gus Ridding a, b Philip J. Schluter f, g Jon A. Hyett c, d Andrew C. McLennan a, c, e a
Maternal Fetal Medicine Unit, Royal North Shore Hospital, b Northern Clinical School and c Faculty of Medicine, University of Sydney, d Maternal Fetal Medicine Unit, Royal Prince Alfred Hospital, e Sydney Ultrasound for Women, Sydney, N.S.W., and f School of Nursing and Midwifery, The University of Queensland, Brisbane, Qld., Australia; g School of Health Sciences, University of Canterbury, Christchurch, New Zealand
Abstract Introduction: First-trimester uterine artery pulsatility index (PI) measurements form part of an algorithm used to assess the risk of developing pre-eclampsia. The objective of this study was to construct a population-specific reference range for both the lower and mean maternal uterine artery PI at 11–13+6 weeks’ gestation and to assess measurement agreement. Materials and Methods: Reference ranges for mean and lower PI measurements were developed using polynomial regression models following prospective collection of maternal uterine artery PI measurements at 11–13+6 weeks’ gestation. Measurement agreement studies were performed by two experienced operators. Results: Measurements from 298 women were included in the primary study. Polynomial regression indicated no change over gestational age for the lower PI (mean 1.44). There was an inverse relationship between the average PI and gestational age (mean [0.8960 + (2.9771 × CRL–1/2)]2). PI measurement agreement was good– strong (intraclass correlation (ICC) 0.50–0.79) between operators, and within-operator agreement was almost perfect (ICC 0.88–0.93). Conclusions: Reference ranges for both the
© 2014 S. Karger AG, Basel 1015–3837/14/0364–0299$39.50/0 E-Mail [email protected] www.karger.com/fdt
average and lowest PI of the maternal uterine arteries were derived at 11–13+6 weeks’ gestation. This will provide a basis for development of auditable standards for first-trimester uterine artery Doppler measurements. The PI measurements © 2014 S. Karger AG, Basel are reproducible and reliable.
Introduction
Pre-eclampsia is a major cause of maternal and fetal mortality and morbidity [1]. Doppler examination of maternal uterine arteries has been used in the prediction of subsequent development of pre-eclampsia [2–5]. Typically this has been performed in the second trimester, but the predictive value is poor and there is no proven effective intervention [6, 7]. Recent studies have shown that first-trimester assessment of maternal uterine arteries can accurately predict those women who will develop early onset pre-eclampsia (ePET) [4, 8, 9]. Meta-analyses stratified by gestation suggest that when aspirin is given prior to 16 weeks’ gestation, it is effective in reducing the prevalence and in ameliorating the effects of severe pre-eclampsia [10, 11]. The most clinically relevant interpretation of the acquired pulsatility index (PI) measurements has not yet Dr. Andrew McLennan Level 1 56 Neridah Street Chatswood, NSW 2067 (Australia) E-Mail amclennan @ sufw.com.au
Downloaded by: WMed Library 141.218.1.105 - 1/23/2015 8:55:26 AM
Key Words Uterine artery Doppler · Pre-eclampsia · First trimester · Ultrasound · Reference range
Materials and Methods Study Design A prospective repeated-measure study, conducted at one public hospital and one private obstetric ultrasound company across several sites in Sydney, Australia. Participants Between May 2011 and April 2012, women attending the two facilities for first-trimester aneuploidy screening were assessed for eligibility and provided with information about the study. Those willing to participate provided consent, and information on maternal age, body mass index (BMI), smoking status, parity, ethnicity and method of pregnancy conception was recorded. Inclusions and Exclusions Women were eligible for inclusion in the study if they had a singleton pregnancy with a crown-rump length (CRL) between 45 and 84 mm at the time of examination, the FMF guidelines for accurate PI measurement were met and Doppler velocimetry was recorded from both left and right uterine arteries [15, 16]. Women with multiple pregnancies, a history of pregnancy-induced hypertension (or intrauterine growth restriction) affecting a previous pregnancy, or pregnancies with fetuses affected by a structural or chromosomal abnormality were excluded. Women who subsequently developed pre-eclampsia or intrauterine growth restriction in this pregnancy were also excluded from the analysis. Pregnancy outcome information was obtained in 92% of the cohort from hospital records or by self-report.
300
Fetal Diagn Ther 2014;36:299–304 DOI: 10.1159/000361021
Equipment and Procedure Transabdominal assessment of uterine artery PI was performed by seven experienced operators. In brief, this involved identification of the vessel as close to the internal cervical os as possible in a sagittal plane, using a 2 mm gate to sample the waveform with an angle of insonation
Received: December 30, 2013 Accepted after revision: February 28, 2014 Published online: August 1, 2014
Uterine Artery Pulsatility Index Assessment at 11–13+6 Weeks’ Gestation Gus Ridding a, b Philip J. Schluter f, g Jon A. Hyett c, d Andrew C. McLennan a, c, e a
Maternal Fetal Medicine Unit, Royal North Shore Hospital, b Northern Clinical School and c Faculty of Medicine, University of Sydney, d Maternal Fetal Medicine Unit, Royal Prince Alfred Hospital, e Sydney Ultrasound for Women, Sydney, N.S.W., and f School of Nursing and Midwifery, The University of Queensland, Brisbane, Qld., Australia; g School of Health Sciences, University of Canterbury, Christchurch, New Zealand
Abstract Introduction: First-trimester uterine artery pulsatility index (PI) measurements form part of an algorithm used to assess the risk of developing pre-eclampsia. The objective of this study was to construct a population-specific reference range for both the lower and mean maternal uterine artery PI at 11–13+6 weeks’ gestation and to assess measurement agreement. Materials and Methods: Reference ranges for mean and lower PI measurements were developed using polynomial regression models following prospective collection of maternal uterine artery PI measurements at 11–13+6 weeks’ gestation. Measurement agreement studies were performed by two experienced operators. Results: Measurements from 298 women were included in the primary study. Polynomial regression indicated no change over gestational age for the lower PI (mean 1.44). There was an inverse relationship between the average PI and gestational age (mean [0.8960 + (2.9771 × CRL–1/2)]2). PI measurement agreement was good– strong (intraclass correlation (ICC) 0.50–0.79) between operators, and within-operator agreement was almost perfect (ICC 0.88–0.93). Conclusions: Reference ranges for both the
© 2014 S. Karger AG, Basel 1015–3837/14/0364–0299$39.50/0 E-Mail [email protected] www.karger.com/fdt
average and lowest PI of the maternal uterine arteries were derived at 11–13+6 weeks’ gestation. This will provide a basis for development of auditable standards for first-trimester uterine artery Doppler measurements. The PI measurements © 2014 S. Karger AG, Basel are reproducible and reliable.
Introduction
Pre-eclampsia is a major cause of maternal and fetal mortality and morbidity [1]. Doppler examination of maternal uterine arteries has been used in the prediction of subsequent development of pre-eclampsia [2–5]. Typically this has been performed in the second trimester, but the predictive value is poor and there is no proven effective intervention [6, 7]. Recent studies have shown that first-trimester assessment of maternal uterine arteries can accurately predict those women who will develop early onset pre-eclampsia (ePET) [4, 8, 9]. Meta-analyses stratified by gestation suggest that when aspirin is given prior to 16 weeks’ gestation, it is effective in reducing the prevalence and in ameliorating the effects of severe pre-eclampsia [10, 11]. The most clinically relevant interpretation of the acquired pulsatility index (PI) measurements has not yet Dr. Andrew McLennan Level 1 56 Neridah Street Chatswood, NSW 2067 (Australia) E-Mail amclennan @ sufw.com.au
Downloaded by: WMed Library 141.218.1.105 - 1/23/2015 8:55:26 AM
Key Words Uterine artery Doppler · Pre-eclampsia · First trimester · Ultrasound · Reference range
Materials and Methods Study Design A prospective repeated-measure study, conducted at one public hospital and one private obstetric ultrasound company across several sites in Sydney, Australia. Participants Between May 2011 and April 2012, women attending the two facilities for first-trimester aneuploidy screening were assessed for eligibility and provided with information about the study. Those willing to participate provided consent, and information on maternal age, body mass index (BMI), smoking status, parity, ethnicity and method of pregnancy conception was recorded. Inclusions and Exclusions Women were eligible for inclusion in the study if they had a singleton pregnancy with a crown-rump length (CRL) between 45 and 84 mm at the time of examination, the FMF guidelines for accurate PI measurement were met and Doppler velocimetry was recorded from both left and right uterine arteries [15, 16]. Women with multiple pregnancies, a history of pregnancy-induced hypertension (or intrauterine growth restriction) affecting a previous pregnancy, or pregnancies with fetuses affected by a structural or chromosomal abnormality were excluded. Women who subsequently developed pre-eclampsia or intrauterine growth restriction in this pregnancy were also excluded from the analysis. Pregnancy outcome information was obtained in 92% of the cohort from hospital records or by self-report.
300
Fetal Diagn Ther 2014;36:299–304 DOI: 10.1159/000361021
Equipment and Procedure Transabdominal assessment of uterine artery PI was performed by seven experienced operators. In brief, this involved identification of the vessel as close to the internal cervical os as possible in a sagittal plane, using a 2 mm gate to sample the waveform with an angle of insonation
