Development of standard definitions and grading for Maternal and Fetal Adverse Event Terminology.

OBJECTIVE: Adverse event (AE) monitoring is central to assessing therapeutic safety. The lack of a comprehensive framework to define and grade maternal and fetal AEs in pregnancy trials severely limits understanding risks in pregnant women. We created AE terminology to improve safety monitoring for developing pregnancy drugs, devices and interventions. METHOD: Existing severity grading for pregnant AEs and definitions/indicators of 'severe' and 'life-threatening' conditions relevant to maternal and fetal clinical trials were identified through a literature search. An international multidisciplinary group identified and filled gaps in definitions and severity grading using Medical Dictionary for Regulatory Activities (MedDRA) terms and severity grading criteria based on Common Terminology Criteria for Adverse Event (CTCAE) generic structure. The draft criteria underwent two rounds of a modified Delphi process with international fetal therapy, obstetric, neonatal, industry experts, patients and patient representatives. RESULTS: Fetal AEs were defined as being diagnosable in utero with potential to harm the fetus, and were integrated into MedDRA. AE severity was graded independently for the pregnant woman and her fetus. Maternal (n = 12) and fetal (n = 19) AE definitions and severity grading criteria were developed and ratified by consensus. CONCLUSIONS: This Maternal and Fetal AE Terminology version 1.0 allows systematic consistent AE assessment in pregnancy trials to improve safety.

Procedural, pregnancy, and short-term outcomes after fetal aortic valvuloplasty.

OBJECTIVES: We aimed to evaluate the effect of technical aspects of fetal aortic valvuloplasty (FAV) on procedural risks and pregnancy outcomes. BACKGROUND: FAV is performed in cases of severe mid-gestation aortic stenosis with the goal of preventing hypoplastic left heart syndrome (HLHS). METHODS: The International Fetal Cardiac Intervention Registry was queried for fetuses who underwent FAV from 2002 to 2018, excluding one high-volume center. RESULTS: The 108 fetuses had an attempted cardiac puncture (mean gestational age [GA] 26.1 ± 3.3 weeks). 83.3% of attempted interventions were technically successful (increased forward flow/new aortic insufficiency). The interventional cannula was larger than 19 g in 70.4%. More than one cardiac puncture was performed in 25.0%. Intraprocedural complications occurred in 48.1%, including bradycardia (34.1%), pericardial (22.2%) or pleural effusion (2.7%) requiring drainage, and balloon rupture (5.6%). Death within 48 hr occurred in 16.7% of fetuses. Of the 81 patients born alive, 59 were discharged home, 34 of whom had biventricular circulation. More than one cardiac puncture was associated with higher complication rates (p < .001). Larger cannula size was associated with higher pericardial effusion rates (p = .044). On multivariate analysis, technical success (odds ratio [OR] = 10.9, 95% confidence interval [CI] = 2.2-53.5, p = .003) and later GA at intervention (OR = 1.5, 95% CI = 1.2-1.9, p = .002) were associated with increased odds of live birth. CONCLUSIONS: FAV is an often successful but high-risk procedure. Multiple cardiac punctures are associated with increased complication and fetal mortality rates. Later GA at intervention and technical success were independently associated with increased odds of live birth. However, performing the procedure later in gestation may miss the window to prevent progression to HLHS.

Fetal Cardiac Intervention for Pulmonary Atresia with Intact Ventricular Septum: International Fetal Cardiac Intervention Registry.

INTRODUCTION: Invasive fetal cardiac intervention (FCI) for pulmonary atresia with intact ventricular septum (PAIVS) and critical pulmonary stenosis (PS) has been performed with small single-institution series reporting technical and physiological success. We present the first multicenter experience. OBJECTIVES: Describe fetal and maternal characteristics of those being evaluated for FCI, including pregnancy/neonatal outcome data using the International Fetal Cardiac Intervention Registry (IFCIR). METHODS: We queried the IFCIR for PAIVS/PS cases evaluated from January 2001 to April 2018 and reviewed maternal/fetal characteristics, procedural details, pregnancy and neonatal outcomes. Data were analyzed using standard descriptive statistics. RESULTS: Of the 84 maternal/fetal dyads in the registry, 58 underwent pulmonary valvuloplasty at a median gestational age of 26.1 (21.9-31.0) weeks. Characteristics of fetuses undergoing FCI varied in terms of tricuspid valve (TV) size, TV regurgitation, and pulmonary valve patency. There were fetal complications in 55% of cases, including 7 deaths and 2 delayed fetal losses. Among those who underwent successful FCI, the absolute measurement of the TV increased by 0.32 (±0.17) mm/week from intervention to birth. Among 60 liveborn with known outcome, there was a higher percentage having a biventricular circulation following successful FCI (87 vs. 43%). CONCLUSIONS: Our data suggest a possible benefit to fetal therapy for PAIVS/PS, though rates of technically unsuccessful procedures and procedure-related complications, including fetal loss were substantial. FCI criteria are extremely variable, making direct comparison to nonintervention patients challenging and potentially biased. More uniform FCI criteria for fetuses with PAIVS/PS are needed to avoid unnecessary procedures, expose only fetuses most likely to sustain a benefit, and to enable comparisons to be made with nonintervention patients.

Attitudes of clinicians toward cardiac surgery and trisomy 18.

Trisomy 18 is an autosomal trisomy condition characterized by minor to major birth defects, severe disabilities, and high rates of pre- and postnatal mortality. Interventions for these infants have traditionally been withheld with focus instead on palliative support. The issues and attitudes surrounding corrective surgery of congenital heart defects, which is a birth defect that occurs in approximately 90% of infants with trisomy 18, is of our study's interest as recent literature has indicated that cardiac surgery is being performed and may lead to improved survival compared to palliative care. Thus, our study aimed to describe clinician attitudes toward cardiac surgery and trisomy 18. We surveyed 378 clinicians from multiple specialties, including genetic counselors, involved in the pre- and postnatal care of infants with trisomy 18. Descriptive statistics were performed to describe all clinicians' responses, and a secondary analysis with stratifications by clinician type was also performed. Forty-eight percent (n = 378) of clinicians felt it was appropriate to discuss the option of cardiac surgery. Ethical concerns and insufficient outcome data were the most agreed upon reasons for not offering cardiac surgery. Trisomy 18 not being uniformly lethal and expressed parental wishes were the most agreed upon justifications for offering surgery. Clinicians felt the discussion of the option of cardiac surgery is appropriate, however are hesitant due to ethical concerns and insufficient outcome data. Results from this study aim to promote discussion and collaboration among clinicians to improve consistency in patient care.

Clinical Monitoring of Sacrococcygeal Teratoma.

BACKGROUND: Sacrococcygeal teratomas (SCT) are often highly vascularized and may result in high-output cardiac failure, polyhydramnios, fetal hydrops, and demise. Delivery is guided by the SCT to fetus volume ratio (SCTratio), SCT growth rate, and cardiac output indexed for weight (CCOi). METHODS: We compared measurements and outcome in 12 consecutive fetuses referred with SCT. Adverse outcomes were: fetal surgery, delivery < 32 gestational weeks or neonatal demise. Only SCTratio and CCOi were used to manage the cases. SCT vascularization index (VI%) was derived from the 3D virtual organ computer-aided analysis (VOCAL) software. The SCTModel (modified from acardiac twins) calculated a hypothetical SCT draining vein size and derived a risk line, using diameters of the superior and inferior vena cava, the azygous and umbilical veins. VI% and a model of systemic and umbilical venous volumes (SCTModel) were tested as indicators for outcome in SCT. RESULTS: Fetuses were monitored from 20.1 to 36.4 gestational weeks and 5/12 had adverse outcomes: 1 had successful open fetal surgery at 23.8 weeks and delivered at term, 4 delivered at < 32 weeks with 3/4 having neonatal demise between 25 and 29 weeks. VI% was significantly higher in cases with adverse outcomes (mean 10.3 [8.9-11.6] vs. 4.4 [3.4-5.3], p < 0.0001). The additional fraction of the fetal cardiac output required to perfuse the SCT-draining vein (XSCO%) (p = 0.46), SCTratio (p = 0.08), and CCOi (p = 0.64) were not significant. All cases with adverse outcome had VI% > 8%. The SCTModel risk line predicted nonadverse outcomes well but lacked data in 2/5 cases with adverse outcomes. CONCLUSIONS: VI% is a significant indicator of SCT cases with adverse outcomes and combined with SCTratio may guide timing of delivery better than current measures.

The Influence of Blood Pressure on Fetal Aortic Distensibility: An Animal Validation Study.

BACKGROUND/AIMS: Aortic distension waveforms describe the change in diameter or cross-sectional area over the cardiac cycle. We aimed to validate the association of aortic fractional area change (AFAC) with blood pressure (BP) in a fetal lamb model. METHODS: Four pregnant ewes underwent open fetal surgery under general anesthesia at 107-120 gestational days. A 4-Fr catheter was introduced into the fetal femoral artery and vein, or the carotid artery and jugular vein. The thoracic aorta was imaged using real-time ultrasound; AFAC was calculated using offline speckle tracking software. Measurements of invasive BP and AFAC were obtained simultaneously and averaged over 10 cardiac cycles. BP was increased by norepinephrine infusion and the association of aortic distensibility with BP was assessed. RESULTS: Baseline measurements were obtained from 4 lambs, and changes in aortic distensibility with increasing BP were recorded from 3 of them. A positive correlation was found between AFAC and systolic BP (r = 0.692, p = 0.001), diastolic BP (r = 0.647, p = 0.004), mean BP (r = 0.692, p = 0.001), and BP amplitude (r = 0.558, p = 0.016) controlled for heart rate. No association was found between BP and maximum or minimum aortic area. CONCLUSION: AFAC provides a quantifiable measure of aortic distensibility and correlates with systolic BP, diastolic BP, mean BP, and BP amplitude in a fetal lamb model.

Recipient umbilical artery elongation (redundancy) in twin-twin transfusion syndrome.

BACKGROUND: Chronic hypertension in adults causes arterial lengthening in major arteries, but the effects of early fetal hypertension on the twin-twin transfusion syndrome recipient's vascular architecture remains unknown. OBJECTIVE: We hypothesize that arterial cord redundancy is related to recipient hypertension and subsequent heart failure. Our objectives were to: (1) establish a 3-dimensional color Doppler ultrasound method of measuring umbilical arterial length relative to its corresponding venous segment in the umbilical cord using artery vein angle; (2) compare recipient artery vein angle to gestational age-matched controls; and (3) test the association of artery vein angle with recipient heart failure. STUDY DESIGN: We compared 3 groups prospectively: twin-twin transfusion syndrome pregnancies undergoing fetoscopic laser surgery (preoperatively) and 2 groups of gestational age-matched controls: uncomplicated monochorionic-diamniotic twin pregnancies and healthy singletons. Using a 3-dimensional color-Doppler volume image of 5 cm of cord near the placental insertion, we traced the umbilical artery and vein producing umbilical artery:vein length, (artery vein index) and measured the artery vein angle between umbilical artery and vein. Correlation of artery vein angle to twin-twin transfusion syndrome stage, maximum vertical pocket, umbilical arterial indices, ductus venosus Doppler, and brain natriuretic peptide were performed. We used pulsed-wave and tissue Doppler to measure tissue Doppler velocities and indexed cardiac output and correlated these with artery vein angle. Comparative statistics, including multivariable linear regression, examined the relationship between umbilical arterial Doppler indices and artery vein angle. RESULTS: Artery vein angle and artery vein index correlated significantly (R2, 0.86; P < .0001), hence, artery vein angle was used for analysis. Mean artery vein angle was 33.1 ± 31.5 degrees in recipients (n = 44), 9.5 ± 6 degrees in monochorionic-diamniotic (n = 11; 22 fetuses), and 8.9 ± 8.3 degrees in singleton controls (n = 16) (P < .001). An artery vein angle ≥26 degrees (>95th percentile for controls) was measured in 52% recipients. Artery vein angle was higher in twin-twin transfusion syndrome stage 3R vs 1 (P = .001). Artery vein angle increased with increasing umbilical arterial pulsatility index (P < .001), and decreased with increasing resistance index (P = .02) after adjusting for gestational age. Interrater agreements to categorize abnormal artery vein angle values was 95% (P < .001). Abnormal ductus venosus Doppler and elevated recipient amniotic fluid N-terminal pro-brain natriuretic peptide/protein levels correlated significantly with artery vein angle. Abnormal artery vein angles were associated with decreased indexed cardiac output, lower tissue Doppler velocities, higher right-sided Tei indices, and severe tricuspid regurgitation. CONCLUSION: Umbilical arterial lengthening occurs in 52% of recipients and is associated with abnormal Doppler flows, low systolic tissue Doppler velocities, reduced cardiac output, and elevated markers of cardiac failure. This may reflect chronicity and severity of hypertension in the recipient fetus. Further research is needed to explore the mechanisms of elongation and long-term implications.

Acardiac twin pregnancies part II: Fetal risk of chorangioma and sacrococcygeal teratoma predicted by pump/acardiac umbilical vein diameters.

BACKGROUND: We recently published pump/acardiac umbilical venous diameter (UVD) ratios, representing the pump twin's excess cardiac output fraction, of 27 acardiac twin pregnancies. There was a clear separation between the 17 pump twins that had life-threatening complications and the 10 that did not. The hypothesis of this study is that placental chorangioma and sacrococcygeal teratoma (SCT), tumors whose perfusion also causes high-output complications, have the same fetal outcome as pump twins when perfusion of the tumor requires the same excess cardiac output fraction. METHODS: We compared the three fetoplacental circulations. Fetuses with a placental chorangioma and acardiac twin pregnancies both have their feeding artery and draining vein located at the placental cord insertion. In contrast, SCT lacks a prescribed feeding artery and draining vein. We, therefore, had to modify our model to assume that the diameter of the hypothetical draining vein is related to the flow difference between inferior vena cava and superior vena cava. The latter flow has been estimated sonographically and is the same as the inferior vena cava flow in the absence of an SCT. Furthermore, a simple modification accounts for the different location of the tumor with respect to the placental cord insertion. RESULTS: We propose to apply the clinical pump/acardiac UVD ratios to pregnancies complicated by placental chorangiomas and the modified pump/acardiac UVD ratios for SCT. CONCLUSION: Risk prediction of these rare fetal tumors may be possible based on application of data on excess cardiac output fractions from pump/acardiac UVD ratios and will require future clinical validation. Birth Defects Research (Part A) 106:733-738, 2016. © 2016 Wiley Periodicals, Inc.

Fetal cardiovascular hemodynamics in twin-twin transfusion syndrome.

Twin-twin transfusion syndrome (TTTS) complicates 10-15% of monochorionic-diamniotic (MCDA) pregnancies. It originates from unbalanced transfer of fluid and vasoactive mediators from one twin to its co-twin via placental anastomoses. This results in hypovolemia in the donor and hypervolemia and vasoconstriction in the recipient twin. Consequently, the recipient demonstrates cardiovascular alterations including atrioventricular valve regurgitation, diastolic dysfunction, and pulmonary stenosis/atresia that do not necessarily correlate with Quintero-stages. Selective fetoscopic laser photocoagulation of placental vascular anastomoses disrupts the underlying pathophysiology and usually improves cardiovascular function in the recipient with normalization of systolic and diastolic function within weeks after treatment. Postnatal studies have demonstrated early decreased arterial distensibility in ex-donor twins, but 10-year follow up is encouraging with survivors showing normal cardiovascular function after TTTS. However, prediction and appropriate early management of TTTS remain poor. Assessment of the cardiovascular system provides additional insight into the pathophysiology and severity of TTTS and may permit more targeted early surveillance of MCDA pregnancies in future. It should form an integral part of the diagnostic algorithm.

Foetal cardiac function: assessing new technologies.

Assessment of foetal cardiac function is more challenging than in the adult, in whom emerging technologies are tested. The postnatal cardio-respiratory interaction is replaced by the cardio-placental circulation and impedance of the brain, and distal vascular beds play an important role in modulating flow to enable its redistribution in the foetal body. Prenatal specialists, comprising obstetricians and cardiologists, have tested a variety of traditional methodologies, as well as non-Doppler offline ultrasound methods in the foetus. This article reviews the development of techniques, outlines their use, and draws attention to pitfalls in adapting technologies validated in the adult heart to the small, fast beating, remote, and largely ungated foetal heart.

Foetal therapy, what works? An overview.

The update course in foetal cardiology held by the Fetal Working Group of the Association for European Paediatric and Congenital Cardiology in Istanbul in May 2012 included a session on foetal cardiac therapy. In the introductory overview to this symposium, we critically examine the level of evidence supporting or refuting proposed foetal cardiac therapies including transplacental treatment of foetal tachyarrhythmias, steroid treatment in foetal atrioventricular block, and foetal aortic valvuloplasty. In summary, the evidence for the efficiency and safety of currently available foetal cardiac therapies is low, with no therapy based on a randomised controlled trial. Transplacental treatment of foetal tachycardia is generally accepted as effective and safe, based on extensive and widespread clinical experience; however, there is no consensus on which drugs are the most effective in different electrophysiological situations. Randomised studies may be able to resolve this, but this is complicated because tachyarrhythmias are relatively rare conditions, the foetus is not accessible for direct treatment, and it is the healthy mother who accepts treatment she does not need on behalf of her foetus. The indications for steroid treatment in foetal atrioventricular block and for foetal valvuloplasty are even more controversial. Although randomised trials would be desirable, the practical issues of recruiting sufficient sample sizes and controlling for variation in practice across multiple sites is not to be underestimated. Multicentre registries, analysed free of bias, may be an alternative way to improve the evidence base of foetal cardiac therapy.

Ventricular strain changes in monochorionic twins with and without twin-to-twin transfusion syndrome.

OBJECTIVE: The objective of the study was to investigate whether vector velocity imaging (VVI), a non-Doppler speckle tracking ultrasound technology, is feasible in twin pregnancies and can aid management of twin-twin transfusion syndrome (TTTS). STUDY DESIGN: Twenty-seven women pregnant with monochorionic diamniotic twins affected by TTTS and 28 monochorionic pregnancies that did not develop TTTS were included in a prospective case-control study at a fetal medicine center. Fetal echocardiograms were recorded with dummy electrocardiography to retain original frame rates when exported for offline speckle tracking analysis using Syngo-VVI software (Siemens Corp, Munich, Germany). Right and left ventricular (LV) free wall Lagrangian strain was measured from the original coordinates. Within-twin pair ventricular strain differences including relationship to Quintero staging and response to laser therapy for TTTS were analyzed by Wilcoxon signed-rank test. RESULTS: The VVI strain measurements could be analyzed in 182 of 200 TTTS and 96 of 112 non-TTTS control ventricles. Within-pair strain was concordant in non-TTTS controls. Recipient LV strain was reduced at all Quintero stages compared with donors (P < .01). Recipient right ventricular strain was reduced only in stages 3 and 4 (P < .01). Strain improved at a median of 2 weeks following successful laser therapy. Intertwin differences in strain were independent of weight discordance. CONCLUSION: Recipient LV strain is reduced in stages 1 and 2 TTTS. Within-pair strain discordance may distinguish early TTTS from growth discordance and guide timing of and management following treatment.

Isolated atrioventricular block in the fetus: a retrospective, multinational, multicenter study of 175 patients.

BACKGROUND: Isolated complete atrioventricular block in the fetus is a rare but potentially lethal condition in which the effect of steroid treatment on outcome is unclear. The objective of this work was to study risk factors associated with death and the influence of steroid treatment on outcome. METHODS AND RESULTS: We studied 175 fetuses diagnosed with second- or third-degree atrioventricular block (2000-2007) retrospectively in a multinational, multicenter setting. In 80% of 162 pregnancies with documented antibody status, atrioventricular block was associated with maternal anti-Ro/SSA antibodies. Sixty-seven cases (38%) were treated with fluorinated corticosteroids for a median of 10 weeks (1-21 weeks). Ninety-one percent were alive at birth, and survival in the neonatal period was 93%, similar in steroid-treated and untreated fetuses, regardless of degree of block and/or presence of anti-Ro/SSA. Variables associated with death were gestational age < 20 weeks, ventricular rate ≤ 50 bpm, fetal hydrops, and impaired left ventricular function at diagnosis. The presence of ≥ 1 of these variables was associated with a 10-fold increase in mortality before birth and a 6-fold increase in the neonatal period independently of treatment. Except for a lower gestational age at diagnosis in treated than untreated (23.4 ± 2.9 versus 24.9 ± 4.9 weeks; P=0.02), risk factors were distributed equally between treatment groups. Two-thirds of survivors had a pacemaker by 1 year of age; 8 children developed cardiomyopathy. CONCLUSIONS: Risk factors associated with a poor outcome were gestation < 20 weeks, ventricular rate ≤ 50 bpm, hydrops, and impaired left ventricular function. No significant effect of treatment with fluorinated corticosteroids was seen.

Assessment of fetal myocardial deformation using speckle tracking techniques.

OBJECTIVE: To report the current status of speckle tracking techniques in evaluation of fetal myocardial deformation. METHODS: A variety of non-Doppler ultrasound methods are available using offline analysis of standard four-chamber and short axis views of the heart. RESULTS: Most reports have used techniques developed for the measurement of strain and strain rate in the adult heart and produced conflicting descriptions of gestational changes in strain. Myocardial velocities usually reflect mean modal velocities and are lower than the peak velocities obtained using Doppler techniques. CONCLUSIONS: In the fetus, most current methods of acquisition result in frame rates that are too low, and the fetal heart size is too small to achieve reliable measures of fetal myocardial deformation.

Fetal longitudinal myocardial function assessment by anatomic M-mode.

AIM: To evaluate the feasibility of offline anatomic M-mode (AMM) to study fetal atrioventricular annulus long-axis displacement (LAD) and compare its performance against real-time conventional M-mode (MM). MATERIAL AND METHODS: Paired AMM and MM LAD studies were recorded prospectively in 54 fetuses, and performance was compared. Insonation angles were less than 30° in all but 4 cases. The overall feasibility of AMM was tested in a composite total sample of 91 normal singleton pregnancies (median gestational age 23⁺6 weeks, range 12-36). AMM LAD was measured by placement of a virtual M-mode line on digitally stored raw data of fetal 4-chamber video loops. We studied annulus LAD at the lateral mitral (left ventricle; LV), proximal mitral (intraventricular septum; IVS), and lateral tricuspid (right ventricle; RV) myocardial segments. We compared LAD and its regression with gestational age measured using both methods in paired studies and AMM in the whole cohort. RESULTS: Annulus LAD was measured using AMM, in all cases and segments, irrespective of cardiac axis alignment to the ultrasound beam. Good correlation existed between AMM and MM (RV r = 0.901, LV r = 0.899, IVS r = 0.815, p < 0.001). AMM recorded higher LAD values than MM in RV [mean 6.17 (SD 1.46) vs. 5.82 (SD 1.74) mm, p = 0.002] and LV [mean 4.18 (SD 1.11) vs. 3.98 (SD 1.12), p = 0.007]. Both methods showed LAD in RV > LV > IVS and a significant gestational increase in LAD values in all segments (p < 0.001) CONCLUSIONS: AMM permits offline evaluation of fetal longitudinal myocardial function in routinely obtained 2D fetal heart images with similar values to conventional MM in paired studies recorded <30°.

Myocardial strain abnormalities in fetal congenital heart disease assessed by speckle tracking echocardiography.

OBJECTIVES: To compare myocardial deformation patterns in fetuses with congenital heart disease (CHD) with our reference range using speckle tracking echocardiography. METHODS: We prospectively stored and analyzed 4-chamber loops of 28 fetuses with CHD (median gestation 27 weeks, range 20.9-37.0). The peak longitudinal left (LVs) and right (RVs) ventricular free wall Lagrangian strain and LV/RV strain ratio were measured from Syngo VVI software- (Siemens) derived original coordinates. Strain values from the first examination were compared with normative data from the same population using ANOVA with post hoc tests and serial examinations described in 14 fetuses. RESULTS: Simple shunt lesions (0.82) and shunts with pulmonary stenosis or atresia (0.93) had reduced mean LV/RV strain ratios compared to normal fetuses (1.01; 95% CI 0.97-1.05). Fetuses with hypoplastic left heart had the lowest (0.29), and those with Ebstein the highest (1.55), LV:RV ratio. Serial measurements showed increased LVs in aortic coarctation and aortic stenosis, but not in one developing important mitral regurgitation. Increased right ventricular loading in a fetus developing pulmonary regurgitation was associated with increasing RVs. CONCLUSIONS: Myocardial strain reflects the changing physiology of fetal CHD. Speckle tracking might be a useful tool to study the progress of myocardial function in affected fetuses.

Morphological and physiological predictors of fetal aortic coarctation.

BACKGROUND: Prenatal diagnosis of aortic coarctation suffers from high false-negative rates at screening and poor specificity. METHODS AND RESULTS: This retrospective study tested the applicability of published aortic arch and ductal Z scores (measured just before the descending aorta in the 3-vessel and tracheal view) and their ratio on 200 consecutive normal controls at a median of 22+/-0 gestational weeks (range, 15+/-4 to 38+/-4 weeks). Second, this study tested the ability of serial Z scores to distinguish fetuses with coarctation within a cohort with ventricular and/or great arterial disproportion detected at screening or fetal echocardiography. Third, it evaluated the diagnostic significance of associated cardiac lesions, coarctation shelf, and isthmal flow disturbance. We studied 44 fetuses with suspected coarctation at 24+/-0 weeks (range, 17+/-3 to 37+/-4 weeks). Receiver-operating characteristic curves were created. Logistic regression tested the association between z scores, additional cardiac diagnoses, and coarctation. Good separation was found of isthmal Z scores for cases requiring surgery from controls and false-positive cases, and receiver-operating characteristic curves showed an excellent area under the curve for isthmal Z score (0.963) and isthmal-to-ductal ratio (0.969). Serial isthmal Z scores improved to >-2 in suspected cases with normal outcomes; those requiring surveillance or surgery remained <-2. Minor lesions did not increase the diagnostic specificity of coarctation, but isthmal flow disturbance increased the odds ratio of true coarctation versus arch hypoplasia 16-fold. CONCLUSIONS: Isthmal Z scores and isthmal-to-ductal ratio are sensitive indicators of fetal coarctation. Serial measurements and abnormal isthmal flow patterns improve diagnostic specificity and may reduce false positives.

In utero intervention for severe congenital heart disease.

The aim of foetal cardiac therapy is to treat an abnormality at the developmental stage so that the process of cardiac growth, which is complex and relies on the volume and direction of circulating blood as well as genetic determinants, can continue. In reality, most cardiac interventions are palliative; hence, major abnormalities are still present at birth. Nevertheless, tangible benefits following successful foetal intervention include improved haemodynamics and reduction in secondary damage leading to better postnatal outcomes. In cases of semilunar valve stenosis, or atresia, foetal valvuloplasty aims to achieve a biventricular, rather than univentricular, circulation. Opening and stenting a restrictive atrial foramen may preserve the pulmonary function in cases of hypoplastic left heart syndrome, thereby increasing the chances of successful postnatal surgery. More recent endeavours include percutaneous implantation of a miniaturised pacemaker to treat complete heart block and the promotion of left-sided heart growth by chronic maternal hyperoxygenation. The true clinical benefit of these interventions over natural history remains uncertain because of the paucity of appropriate randomised controlled trials (RCTs). Foetal cardiac therapy must now move from a pioneering approach to one that is supported by evidence, as has been done successfully for other foetal therapies.

In-utero intervention for severe congenital heart disease.

The concept of fetal therapy is well established for many disorders diagnosed before birth but practical issues regarding its introduction into clinical practice are more difficult. Cardiac malformations are common, with major lesions affecting about 3.5 per thousand pregnancies; however, only a small proportion of these is likely to benefit from an intrauterine intervention. In addition, there are no good animal models of human cardiac disease and our knowledge of the underlying mechanisms is at best sketchy. This combination of factors has resulted in slow progress in developing effective therapies for the intrauterine management of cardiac disease. Recent research and clinical developments have included percutaneous valvuloplasty for severe aortic and pulmonary stenosis, perforation of the closed or restrictive inter-atrial septum and pacing for complete heart block. Progress in these endeavours has been variable but - overall - shows promise for treatment of the human fetus.

Advances in fetal echocardiography.

The development of fetal echocardiography and success in prenatal cardiac screening programs over the past 30 years has been driven by technical innovation and influenced by the different approaches of the various specialties practicing it. Screening for congenital heart defects no longer focuses on examining a limited number of pregnant women thought to be at increased risk, but instead forms an integrated part of a high-quality anatomical ultrasound performed in the second trimester using the 'five-transverse view' protocol. A prenatal diagnosis is feasible in almost all cardiac lesions and the advantages to parents and to health professionals are well recognized. Prenatal evaluation can usually determine the level of care required at delivery, thereby reducing perinatal morbidity. However, only half of the babies undergoing surgery within the first year of life have a prenatal detection, and practical training programs to support and provide feedback to sonographers remain essential for continued improvement.