Publications by authors named "Lindsey D Allan"

11 Publications

  • Page 1 of 1

Reference Ranges for Pulsed-Wave Doppler of the Fetal Cardiac Inflow and Outflow Tracts from 13 to 36 Weeks' Gestation.

J Am Soc Echocardiogr 2021 May 3. Epub 2021 May 3.

Medway Fetal and Maternal Medicine Centre, Medway Maritime Hospital, Gillingham, United Kingdom; Institute of Medical Sciences, Canterbury Christ Church University, Chatham, United Kingdom.

Background: Doppler assessment of ventricular filling and outflow tract velocities is an integral part of fetal echocardiography, to assess diastolic function, systolic function, and outflow tract obstruction. There is a paucity of prospective data from a large sample of normal fetuses in the published literature. The authors report reference ranges for pulsed-wave Doppler flow of the mitral valve, tricuspid valve, aortic valve, and pulmonary valve, as well as heart rate, in a large number of fetuses prospectively examined at a single tertiary fetal cardiology center.

Methods: The study population comprised 7,885 fetuses at 13 to 36 weeks' gestation with no detectable abnormalities from pregnancies resulting in normal live births. Prospective pulsed-wave Doppler blood flow measurements were taken of the mitral, tricuspid, aortic, and pulmonary valves. The fetal heart rate was recorded at the time of each assessment. Regression analysis, with polynomial terms to assess for linear and nonlinear contributors, was used to establish the relationship between each measurement and gestational age.

Results: The measurement for each cardiac Doppler measurement was expressed as a Z score (difference between observed and expected values divided by the fitted SD corrected for gestational age) and percentile. Analysis included calculation of gestation-specific SDs. Regression equations are provided for the cardiac inflow and outflow tracts.

Conclusions: This study establishes reference ranges for fetal cardiac Doppler measurements and heart rate between 13 to 36 weeks' gestation that may be useful in clinical practice.
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http://dx.doi.org/10.1016/j.echo.2021.04.017DOI Listing
May 2021

Reference Ranges for the Size of the Fetal Cardiac Outflow Tracts From 13 to 36 Weeks Gestation: A Single-Center Study of Over 7000 Cases.

Circ Cardiovasc Imaging 2018 07;11(7):e007575

Harris Birthright Centre for Fetal Medicine, Fetal Medicine Research Institute, King's College Hospital NHS Foundation Trust, London, United Kingdom (T.V.V., R.A., A.S., M.C., L.D.A., K.H.N., V.Z., J.M.S.).

Background: Assessment of the outflow tract views is an integral part of routine fetal cardiac scanning. For some congenital heart defects, notably coarctation of the aorta, pulmonary valve stenosis, and aortic valve stenosis, the size of vessels is important both for diagnosis and prognosis. Existing reference ranges of fetal outflow tracts are derived from a small number of cases.

Methods And Results: The study population comprised 7945 fetuses at 13 to 36 weeks' gestation with no detectable abnormalities from pregnancies resulting in normal live births. Prospective measurements were taken of (1) the aortic and pulmonary valves in diastole at the largest diameter with the valve closed, (2) the distal transverse aortic arch on the 3 vessel and trachea view beyond the trachea at the distal point at its widest systolic diameter, and (3) the arterial duct on the 3 vessel and trachea view at its widest systolic diameter. Regression analysis, with polynomial terms to assess for linear and nonlinear contributors, was used to establish the relationship between each measurement and gestational age. The measurement for each cardiac diameter was expressed as a z score (difference between observed and expected value divided by the fitted SD corrected for gestational age) and percentile. Analysis included calculation of gestation-specific SDs. Regression equations are provided for the cardiac outflow tracts and for the distal transverse aortic arch:arterial duct ratio.

Conclusions: The study established reference ranges for fetal outflow tract measurements at 13 to 36 weeks' gestation that are useful in clinical practice.
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http://dx.doi.org/10.1161/CIRCIMAGING.118.007575DOI Listing
July 2018

Persistently elevated nuchal translucency and the fetal heart.

J Matern Fetal Neonatal Med 2018 Sep 4;31(18):2376-2380. Epub 2017 Jul 4.

a Harris Birthright Research Centre for Fetal Medicine, Fetal Medicine Research Institute, King's College Hospital , Denmark Hill, London , UK.

Objective: To describe the outcome of fifteen cases with an elevated nuchal translucency (NT) which persisted into the second trimester as nuchal edema (NE) >6 mm whom underwent fetal echocardiography.

Materials And Methods: Cases were identified following retrospective review of cardiac and genetic findings in fetuses with NE.

Results: Minor congenital heart disease was identified in 3/15 by the second trimester. Agenesis of the ductus venosus was evident in four. Pulmonary valve stenosis was diagnosed in one fetus at the 20-week scan and hypertrophic cardiomyopathy in one. However, hypertrophic cardiomyopathy or pulmonary valve stenosis was present after birth in all surviving cases by 3 months of age. On the basis of intention to treat, 11/12 survived to delivery and 9/12 survived to 28 days. There were 6 deaths before 14 months of age as a result of severe hypertrophic cardiomyopathy. Noonan syndrome was confirmed with genetic testing in 11/15 cases.

Conclusions: All fetuses with NT and NE had evidence of congenital heart disease at birth, and therefore, late gestation and postnatal review is recommended even when second trimester echocardiogram is considered normal. There is a high prevalence of Noonan syndrome and targeted genetic analysis should be considered. The outcome in these cases is poor.
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http://dx.doi.org/10.1080/14767058.2017.1342804DOI Listing
September 2018

Rationale for and current status of prenatal cardiac intervention.

Authors:
Lindsey D Allan

Early Hum Dev 2012 May 15;88(5):287-90. Epub 2012 Mar 15.

Harris Birthright Centre for Fetal Medicine, King's College Hospital, Denmark Hill, London, SE5 9RS, UK.

The idea of prenatal intervention in congenital heart defects was put forward over 20 years ago, arising from the observation that some forms of cardiac malformation progressed in severity as pregnancy advanced. The simultaneous development of minimally invasive catheter techniques in children, led to the concept of treating the foetal heart directly, in an attempt to prevent the changes which had been observed. Early efforts at prenatal valvuloplasty were largely set aside after poor results and the coincidental development of alternative, increasingly successful, postnatal surgical strategies. However, in the last 10 years or so, some centres have revived and extended the interventional techniques, with some success. The application of these techniques is limited to very few conditions, and suitable cases are relatively uncommon. Exploration of these procedures, therefore, should be limited to very few centres and the results should be closely scrutinised before this becomes an accepted management option.
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http://dx.doi.org/10.1016/j.earlhumdev.2012.02.012DOI Listing
May 2012

Prevalence of increased nuchal translucency in fetuses with congenital cardiac disease and a normal karyotype.

Cardiol Young 2009 Sep 29;19(5):441-5. Epub 2009 Jul 29.

Department of Fetal and Paediatric Cardiology, Evelina Children's Hospital, London, UK.

Objectives: Our aims were to estimate the prevalence of increased nuchal translucency in fetuses with a normal karyotype that were subsequently diagnosed with congenital cardiac disease on fetal echocardiography, and to assess whether there is a link between increased nuchal translucency and specific congenital cardiac malformations.

Methods: We reviewed all patients referred to King's College Hospital and the Evelina Children's Hospital in London for fetal echocardiography between January 1998 and December 2007. We investigated the proportion of chromosomally normal fetuses with congenitally malformed hearts in which nuchal thickness was increased, both overall and with specific defects.

Results: We identified 2133 fetuses with congenital cardiac disease by prenatal echocardiography. Of those, 707 were excluded due to abnormal karyotype, and 690 were excluded due to unknown karyotype. The remaining 736 were eligible for inclusion. Among 481 fetuses with documented congenital cardiac disease and normal chromosomes, making up 23% of the overall cohort, 224 had increased nuchal thickness defined as equal or greater than 2.5 millimetres, this being 0.47 of the inclusive cohort, with 95% confidence intervals from 0.42 to 0.51. These proportions were significantly higher than the expected proportion of the normal population, which was 0.05 (p < 0.001). The only diagnosis for which the proportion of fetuses with nuchal translucency measurement equal or greater than 2.5 millimetres was higher than the others was atrioventricular septal defect, with 0.62 of this cohort having abnormal values, with 95% confidence intervals from 0.47 to 0.77 (p = 0.038).

Conclusion: We found that nearly half of prenatally diagnosed fetuses with congenitally malformed hearts, when examined ultrasonically in the first or early-second trimester, had increased nuchal thickness. We recommend, therefore, referral of all fetuses with increased nuchal translucency for fetal echocardiography.
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http://dx.doi.org/10.1017/S1047951109990655DOI Listing
September 2009

Diagnosis of cardiac anomalies in offspring of women with congenital heart disease: is fetal echocardiography enough?

Authors:
Lindsey D Allan

Nat Clin Pract Cardiovasc Med 2008 Sep 22;5(9):522-3. Epub 2008 Jul 22.

Harris Birthright Fetal Medicine Unit, King's College Hospital, London, UK.

Detailed follow-up in a series of 276 mothers with congenital heart disease--whose children are at increased risk of heart disease--demonstrated that, although a fetal echocardiography is reliable in detecting major disease, some minor lesions are undetectable until after birth. Most of these minor defects will be diagnosed by routine clinical cardiac examination and can be confirmed by pediatric echocardiography.
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http://dx.doi.org/10.1038/ncpcardio1296DOI Listing
September 2008

Prenatal diagnosis of conotruncal malformations: diagnostic accuracy, outcome, chromosomal abnormalities, and extracardiac anomalies.

Am J Perinatol 2006 May 19;23(4):241-5. Epub 2006 Apr 19.

Division of Pediatric Cardiology, New York-Presbyterian Hospital, Columbia University College of Physicians and Surgeons, New York, New York, USA.

The purpose of this study was to determine whether continuing experience in prenatal diagnosis of conotruncal malformations (CTMs) has resulted in improved diagnostic accuracy and outcome. Previous reports have demonstrated particular difficulty with ascertainment of the spatial relationship of the great arteries in patients with CTM. The prognosis for fetuses with CTM was poor. Medical records of 113 consecutive fetuses in whom a CTM (tetralogy of Fallot [TOF], double-outlet right ventricle [DORV], type B aortic arch interruption, transposition of the great arteries [TGA], and persistent truncus arteriosus [TA]) was diagnosed antenatally between 1994 and 2003 were reviewed. The diagnosis of the 91 fetuses with CTM included TOF (n = 32), TGA (n = 29), DORV (n = 22), and TA (n = 8). The great arterial spatial relationship was diagnosed accurately in 84 of the 91 (92%) live-born infants. In the other seven infants with DORV, the great arterial spatial relationship was identified inaccurately. The overall survival to 30 days was 85 of 91 (93%). Twenty-three of 91 (25%) patients had extracardiac anomalies. Genetic diagnosis (amniocentesis) was obtained in 63 of 94 patients; 11 (17%) had chromosomal abnormalities. Maternal glucose tolerance results were obtained in 65 of the 91 patients and were abnormal in 25 of 65 (38%). Prenatal diagnostic accuracy of conotruncal malformations is excellent; the arterial spatial relationship of DORV remains problematic. The populations of fetuses with CTMs who continue to develop to term have an excellent prognosis.
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http://dx.doi.org/10.1055/s-2006-939535DOI Listing
May 2006

The mystery of nuchal translucency.

Authors:
Lindsey D Allan

Cardiol Young 2006 Feb;16(1):11-7

Harris Birthright Unit, King's College Hospital, London, United Kingdom.

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http://dx.doi.org/10.1017/S1047951105002039DOI Listing
February 2006

Counselling following a diagnosis of congenital heart disease.

Prenat Diagn 2004 Dec;24(13):1136-42

Harris Birthright Centre for Fetal Medicine, King's College Hospital, Denmark Hill, London, UK.

Counselling the parents following a diagnosis of fetal congenital heart disease (CHD) is as important a task for the fetal cardiologist, as the skill involved in achieving an accurate diagnosis. The counsellor will base prognosis not only on the diagnosis itself but also on the security of diagnosis, the stage in gestation and potential for change, the association with extracardiac malformations and the known results of treatment. Depending on the gestational age and legal situation the counsellor is operating in, termination of pregnancy may be one of the options to consider and one that should always be raised in discussion. Thus, the parents may be in the position of making a crucial decision concerning the management of the pregnancy on the basis of the information received, so it is vital that the counsellor is truly able to communicate with them, whatever be their level of understanding.
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http://dx.doi.org/10.1002/pd.1071DOI Listing
December 2004

Cardiac anatomy screening: what is the best time for screening in pregnancy?

Authors:
Lindsey D Allan

Curr Opin Obstet Gynecol 2003 Apr;15(2):143-6

Harris Birthright Centre for Fetal Medicine Research, King's College Hospital, London, UK.

Purpose Of Review: To consider the ideal gestational age for cardiac evaluation during pregnancy.

Recent Findings: Screening the heart during routine obstetric ultrasound has become well established and is increasingly successful in the initial detection of major congenital heart disease. When the option of termination of pregnancy is available, the earlier the diagnosis of any major fetal malformation is made, the better for the patient. An important group who have recently been found to be at increased risk of fetal heart malformation are those with increased nuchal translucency measurements, who are identified between 11 and 14 weeks. Thus, screening for fetal anomalies is being attempted much earlier in pregnancy, aided by advances in technology. However, some forms of cardiac malformations do not become evident until the third trimester of pregnancy; as a result, some of the late-developing lesions may go undetected during very early evaluation.

Summary: The ideal timing for screening is a compromise between obtaining adequate images for diagnosis in the majority of routine patients, scanning sufficiently late not to miss late-developing lesions and yet offering diagnosis as early as possible for parents to consider their options, if there are any applicable to their particular diagnosis. For low-risk patients, the best compromise appears to be at around 20 weeks of gestation. For patients at increased risk of congenital heart disease, such as those found to have substantially increased nuchal translucency or those with a family history of the disease, an initial scan to exclude major malformations should be performed by the fetal cardiology expert at 12-14 weeks, with follow-up at around 20 weeks to exclude more minor defects and those lesions which may become evident later.
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http://dx.doi.org/10.1097/00001703-200304000-00009DOI Listing
April 2003