Effectiveness of prenatal screening for congenital heart disease: assessment in a jurisdiction with universal access to health care

Socioeconomic Status and Access to Care for Pediatric and Adult Congenital Heart Disease in Universal Health Coverage Models

Congenital heart disease (CHD) is the most common major congenital anomaly, affecting one in every 100 live births. Whereas over 90% of children born with CHD in low- and middle-income countries cannot access the care they need, early detection, advances in management, and financial risk protection have resulted in over 90% of children with CHD in high-income countries surviving into adulthood. Despite the presence of universal health coverage, barriers to accessing high-quality cardiovascular and non-cardiovascular care for CHD remain common. Lower socioeconomic status has been associated with differential access to cardiac care and poorer outcomes across multiple cardiovascular conditions and subspecialties. In this review article, we describe the relationship between socioeconomic status and access to CHD care in countries with universal health coverage models. We further evaluate notable challenges and opportunities to improve equitable, high-quality CHD care in these countries.

Prenatal detection rates for congenital heart disease using abnormal obstetrical screening ultrasound alone as indication for fetal echocardiography

OBJECTIVE

To determine the live born prenatal detection rate of significant congenital heart disease (CHD) in a large, integrated, multi-center community-based health system using a strategy of referral only of patients with significant cardiac abnormalities on obstetrical screening ultrasound for fetal echocardiography. Detection rates were assessed for screening in both radiology and maternal fetal medicine (MFM). The impact on fetal echocardiography utilization was also assessed.

METHODS

This was a retrospective cohort study using an electronic health record, outside claims databases and chart review to determine all live births between 2016 and 2020 with postnatally confirmed sCHD that were prenatally detectable and resulted in cardiac surgery, intervention, or death within 1 year.

RESULTS

There were 214,486 pregnancies resulting in live births. Prenatally detectable significant CHD was confirmed in 294 infants. Of those 183 were detected for an overall live-born detection rate of 62%. Detection rates in MFM were 75% and in radiology were 52%. The number of fetal echocardiograms needed to detect (NND) sCHD was 7.

CONCLUSIONS

A focus on quality and standardization of obstetrical screening ultrasound with referral to fetal echocardiography for cardiac abnormalities alone achieves benchmark targets for live-born detection of significant CHD requiring fewer fetal echocardiograms.

Diagnostic accuracy of ultrasound screening for fetal structural abnormalities during the first and second trimester of pregnancy in low-risk and unselected populations

BACKGROUND

Prenatal ultrasound is widely used to screen for structural anomalies before birth. While this is traditionally done in the second trimester, there is an increasing use of first-trimester ultrasound for early detection of lethal and certain severe structural anomalies.

OBJECTIVES

To evaluate the diagnostic accuracy of ultrasound in detecting fetal structural anomalies before 14 and 24 weeks' gestation in low-risk and unselected pregnant women and to compare the current two main prenatal screening approaches: a single second-trimester scan (single-stage screening) and a first- and second-trimester scan combined (two-stage screening) in terms of anomaly detection before 24 weeks' gestation.

SEARCH METHODS

We searched MEDLINE, EMBASE, Science Citation Index Expanded (Web of Science), Social Sciences Citation Index (Web of Science), Arts & Humanities Citation Index and Emerging Sources Citation Index (Web of Science) from 1 January 1997 to 22 July 2022. We limited our search to studies published after 1997 and excluded animal studies, reviews and case reports. No further restrictions were applied. We also screened reference lists and citing articles of each of the included studies.

SELECTION CRITERIA

Studies were eligible if they included low-risk or unselected pregnant women undergoing a first- and/or second-trimester fetal anomaly scan, conducted at 11 to 14 or 18 to 24 weeks' gestation, respectively. The reference standard was detection of anomalies at birth or postmortem.

DATA COLLECTION AND ANALYSIS

Two review authors independently undertook study selection, quality assessment (QUADAS-2), data extraction and evaluation of the certainty of evidence (GRADE approach). We used univariate random-effects logistic regression models for the meta-analysis of sensitivity and specificity.

MAIN RESULTS

Eighty-seven studies covering 7,057,859 fetuses (including 25,202 with structural anomalies) were included. No study was deemed low risk across all QUADAS-2 domains. Main methodological concerns included risk of bias in the reference standard domain and risk of partial verification. Applicability concerns were common in studies evaluating first-trimester scans and two-stage screening in terms of patient selection due to frequent recruitment from single tertiary centres without exclusion of referrals. We reported ultrasound accuracy for fetal structural anomalies overall, by severity, affected organ system and for 46 specific anomalies. Detection rates varied widely across categories, with the highest estimates of sensitivity for thoracic and abdominal wall anomalies and the lowest for gastrointestinal anomalies across all tests. The summary sensitivity of a first-trimester scan was 37.5% for detection of structural anomalies overall (95% confidence interval (CI) 31.1 to 44.3; low-certainty evidence) and 91.3% for lethal anomalies (95% CI 83.9 to 95.5; moderate-certainty evidence), with an overall specificity of 99.9% (95% CI 99.9 to 100; low-certainty evidence). Two-stage screening had a combined sensitivity of 83.8% (95% CI 74.7 to 90.1; low-certainty evidence), while single-stage screening had a sensitivity of 50.5% (95% CI 38.5 to 62.4; very low-certainty evidence). The specificity of two-stage screening was 99.9% (95% CI 99.7 to 100; low-certainty evidence) and for single-stage screening, it was 99.8% (95% CI 99.2 to 100; moderate-certainty evidence). Indirect comparisons suggested superiority of two-stage screening across all analyses regarding sensitivity, with no significant difference in specificity. However, the certainty of the evidence is very low due to the absence of direct comparisons.

AUTHORS' CONCLUSIONS

A first-trimester scan has the potential to detect lethal and certain severe anomalies with high accuracy before 14 weeks' gestation, despite its limited overall sensitivity. Conversely, two-stage screening shows high accuracy in detecting most fetal structural anomalies before 24 weeks' gestation with high sensitivity and specificity. In a hypothetical cohort of 100,000 fetuses, the first-trimester scan is expected to correctly identify 113 out of 124 fetuses with lethal anomalies (91.3%) and 665 out of 1776 fetuses with any anomaly (37.5%). However, 79 false-positive diagnoses are anticipated among 98,224 fetuses (0.08%). Two-stage screening is expected to correctly identify 1448 out of 1776 cases of structural anomalies overall (83.8%), with 118 false positives (0.1%). In contrast, single-stage screening is expected to correctly identify 896 out of 1776 cases before 24 weeks' gestation (50.5%), with 205 false-positive diagnoses (0.2%). This represents a difference of 592 fewer correct identifications and 88 more false positives compared to two-stage screening. However, it is crucial to acknowledge the uncertainty surrounding the additional benefits of two-stage versus single-stage screening, as there are no studies directly comparing them. Moreover, the evidence supporting the accuracy of first-trimester ultrasound and two-stage screening approaches primarily originates from studies conducted in single tertiary care facilities, which restricts the generalisability of the results of this meta-analysis to the broader population.

Fetal electrocardiography and artificial intelligence for prenatal detection of congenital heart disease

INTRODUCTION

This study aims to investigate non-invasive electrocardiography as a method for the detection of congenital heart disease (CHD) with the help of artificial intelligence.

MATERIAL AND METHODS

An artificial neural network was trained for the identification of CHD using non-invasively obtained fetal electrocardiograms. With the help of a Bayesian updating rule, multiple electrocardiographs were used to increase the algorithm's performance.

RESULTS

Using 122 measurements containing 65 healthy and 57 CHD cases, the accuracy, sensitivity, and specificity were found to be 71%, 63%, and 77%, respectively. The sensitivity was however 75% and 69% for CHD cases requiring an intervention in the neonatal period and first year of life, respectively. Furthermore, a positive effect of measurement length on the detection performance was observed, reaching optimal performance when using 14 electrocardiography segments (37.5 min) or more. A small negative trend between gestational age and accuracy was found.

CONCLUSIONS

The proposed method combining recent advances in obtaining non-invasive fetal electrocardiography with artificial intelligence for the automatic detection of CHD achieved a detection rate of 63% for all CHD and 75% for critical CHD. This feasibility study shows that detection rates of CHD might improve by using electrocardiography-based screening complementary to the standard ultrasound-based screening. More research is required to improve performance and determine the benefits to clinical practice.

Early Detection of Isolated Severe Congenital Heart Defects Is Associated with a Lower Threshold to Terminate the Pregnancy

INTRODUCTION

Early detection of isolated severe congenital heart defects (CHDs) allows extra time for chromosomal analysis and informed decision making, resulting in improved perinatal management and patient satisfaction. Therefore, the aim of this study was to assess the value of an additional first-trimester screening scan compared to only a second-trimester scan in fetuses diagnosed with isolated severe CHDs. Prenatal detection rate, time of prenatal diagnosis, and pregnancy outcome were evaluated in the Netherlands after implementation of a national screening program.

MATERIALS AND METHODS

We performed a retrospective geographical cohort study and included 264 pre- and postnatally diagnosed isolated severe CHD cases between January 1, 2007, and December 31, 2015, in the Amsterdam region. Severe CHD was defined as potentially life threatening if intervention within the first year of life was required. Two groups were defined: those with a first- and second-trimester anomaly scan (group 1) and those with a second-trimester anomaly scan only (group 2). A first-trimester scan was defined as a scan between 11 + 0 and 13 + 6 weeks of gestation.

RESULTS

Overall, the prenatal detection rate for isolated severe CHDs was 65%; 63% were detected before 24 weeks of gestation (97% of all prenatally detected CHDs). Prenatal detection rate was 70.2% in the group with a first- and second-trimester scan (group 1) and 58% in the group with a second-trimester scan only (group 2) (p < 0.05). Median gestational age at detection was 19 + 6 (interquartile range [IQR] 15 + 4 - 20 + 5) in group 1 versus 20 + 3 (IQR: 20 + 0 - 21 + 1) in group 2 (p < 0.001). In group 1, 22% were diagnosed before 18 weeks of gestation. Termination of pregnancy rate in group 1 and group 2 were 48% and 27%, respectively (p < 0.01). Median gestational age at termination did not differ between the two groups.

CONCLUSION

Prenatal detection rate of isolated severe CHDs and termination of pregnancy rate was higher in the group with both a first- and second-trimester scan. We found no differences between timing of terminations. The additional time after diagnosis allows for additional genetic testing and optimal counseling of expectant parents regarding prognosis and perinatal management, so that well-informed decisions can be made.

The Impact of Neighborhood Socioeconomic Status, Race and Ethnicity, and Language on Prenatal Diagnosis of CHD

Congenital heart disease (CHD) is the most prevalent birth defect. This study aimed to assess whether prenatal diagnosis (PD) of CHD and time of the diagnosis are associated with maternal race, ethnicity, neighborhood SES, and language. In this retrospective cohort study, we analyzed data on 163 patients who underwent surgical intervention for CHD within 30 days of birth between 2011 and 2020 at the University of Maryland Children's Hospital. A neighborhood SES score was calculated using the mother's address at time of discharge and 6 SES variables from the US Census block group data with a previously published method by Diez Roux et al. Neighborhood SES did not impact the likelihood of receiving a PD of CHD; however, patients of Latino ethnicity were 3.2 times and non-English-preferred language patients were 5.1 times more likely to not receive a PD. Patients whose preferred language was a non-English language received a prenatal diagnosis 5.3 weeks later, resulting in the PD being made in the third trimester rather than the second. Patients from the highest quartile SES received an earlier prenatal diagnosis, although this association was less significant when controlling for insurance type and preferred language. Significant disparities in PD of CHD were seen in patients of Latino ethnicity and patients who prefer non-English language. Better understanding of the root causes of these disparities will be important to guide interventions to reduce these disparities.

The electrical heart axis in fetuses with congenital heart disease, measured with non-invasive fetal electrocardiography

OBJECTIVES

To determine if the electrical heart axis in different types of congenital heart defects (CHD) differs from that of a healthy cohort at mid-gestation.

METHODS

Non-invasive fetal electrocardiography (NI-fECG) was performed in singleton pregnancies with suspected CHD between 16 and 30 weeks of gestation. The mean electrical heart axis (MEHA) was determined from the fetal vectorcardiogram after correction for fetal orientation. Descriptive statistics were used to determine the MEHA with corresponding 95% confidence intervals (CI) in the frontal plane of all fetuses with CHD and the following subgroups: conotruncal anomalies (CTA), atrioventricular septal defects (AVSD) and hypoplastic right heart syndrome (HRHS). The MEHA of the CHD fetuses as well as the subgroups was compared to the healthy control group using a spherically projected multivariate linear regression analysis. Discriminant analysis was applied to calculate the sensitivity and specificity of the electrical heart axis for CHD detection.

RESULTS

The MEHA was determined in 127 fetuses. The MEHA was 83.0° (95% CI: 6.7°; 159.3°) in the total CHD group, and not significantly different from the control group (122.7° (95% CI: 101.7°; 143.6°). The MEHA was 105.6° (95% CI: 46.8°; 164.4°) in the CTA group (n = 54), -27.4° (95% CI: -118.6°; 63.9°) in the AVSD group (n = 9) and 26.0° (95% CI: -34.1°; 86.1°) in the HRHS group (n = 5). The MEHA of the AVSD and the HRHS subgroups were significantly different from the control group (resp. p = 0.04 and p = 0.02). The sensitivity and specificity of the MEHA for the diagnosis of CHD was 50.6% (95% CI 47.5% - 53.7%) and 60.1% (95% CI 57.1% - 63.1%) respectively.

CONCLUSION

The MEHA alone does not discriminate between healthy fetuses and fetuses with CHD. However, the left-oriented electrical heart axis in fetuses with AVSD and HRHS was significantly different from the control group suggesting altered cardiac conduction along with the structural defect.

TRIAL REGISTRATION

Clinical trial registration number: NL48535.015.14.

Impact of Socioeconomic Status and Residence Distance on Infant Heart Disease Outcomes in Canada

Background Socioeconomic status (SES) impacts clinical outcomes associated with severe congenital heart disease (sCHD). We examined the impact of SES and remoteness of residence (RoR) on congenital heart disease (CHD) outcomes in Canada, a jurisdiction with universal health insurance. Methods and Results All infants born in Canada (excluding Quebec) from 2008 to 2018 and hospitalized with CHD requiring intervention in the first year were identified. Neighborhood level SES income quintiles were calculated, and RoR was categorized as residing <100 km, 100 to 299 km, or >300 km from the closest of 7 cardiac surgical programs. In-hospital mortality at <1 year was the primary outcome, adjusted for preterm birth, low birth weight, and extracardiac pathology. Among 7711 infants, 4485 (58.2%) had moderate CHD (mCHD) and 3226 (41.8%) had sCHD. Overall mortality rate was 10.5%, with higher rates in sCHD than mCHD (13.3% versus 8.5%, respectively). More CHD infants were in the lowest compared with the highest SES category (27.1% versus 15.0%, respectively). The distribution of CHD across RoR categories was 52.3%, 21.3%, and 26.4% for <100 km, 100 to 299 km, and >300 km, respectively. Although SES and RoR had no impact on sCHD mortality, infants with mCHD living >300 km had a higher risk of mortality relative to those living <100 km (adjusted odds ratio [aOR], 1.43 [95% CI, 1.11-1.84]). Infants with mCHD within the lowest SES quintile and living farthest away had the highest risk for mortality (aOR, 1.74 [95% CI, 1.08-2.81]). Conclusions In Canada, neither RoR nor SES had an impact on outcomes of infants with sCHD. Greater RoR, however, may contribute to higher risk of mortality among infants with mCHD.

Use of fetal tele-echo at small regional hospitals increases the rate of prenatal diagnosis of congenital heart disease

BACKGROUND

To improve the rate of prenatal diagnosis of Congenital heart disease (CHD) in Kentucky, four fetal tele-echocardiography sites were established at regional hospitals in Kentucky: Ashland in 2011, Paducah in 2014, Lexington in 2014, and Owensboro in 2016.

METHODS

A 13-year retrospective review of medical records at Norton Children's Hospital was performed to identify patients with CHD who had cardiac surgery or intervention prior to one year of age. The rate of prenatal diagnosis prior to establishing any fetal tele-echocardiography sites was compared to the rate of prenatal diagnosis after the sites were established. Independent t-tests were used to determine if there was a statistically significant increase in the rate of prenatal diagnosis.

RESULTS

1287 patients had cardiac surgery or cath lab intervention prior to one year of age at our institution from June 2005 to December 2018 and were included in the analysis. Seventeen patients were excluded due to incomplete medical records. The rate of prenatal diagnosis prior to the implementation of the first fetal tele-echocardiography site was 13.8% and after the sites were established, the prenatal diagnosis rate was 39.7% (p < 0.01).

CONCLUSION

Increasing the number of fetal tele-echocardiography sites at small regional hospitals in Kentucky was associated with a statistically significant increase in the rate of prenatal diagnosis for patients less than 1 year of age who had cardiac surgery or cath lab intervention at Norton Children's Hospital in Louisville. Fetal tele-echocardiography is an effective method to improve the rate of prenatal diagnosis in regions served by small regional hospitals with limited access to fetal echocardiography.

First-trimester ultrasound detection of fetal heart anomalies: systematic review and meta-analysis

OBJECTIVES

To determine the diagnostic accuracy of ultrasound at 11-14 weeks' gestation in the detection of fetal cardiac abnormalities and to evaluate factors that impact the detection rate.

METHODS

This was a systematic review of studies evaluating the diagnostic accuracy of ultrasound in the detection of fetal cardiac anomalies at 11-14 weeks' gestation, performed by two independent reviewers. An electronic search of four databases (MEDLINE, EMBASE, Web of Science Core Collection and The Cochrane Library) was conducted for studies published between January 1998 and July 2020. Prospective and retrospective studies evaluating pregnancies at any prior level of risk and in any healthcare setting were eligible for inclusion. The reference standard used was the detection of a cardiac abnormality on postnatal or postmortem examination. Data were extracted from the included studies to populate 2 × 2 tables. Meta-analysis was performed using a random-effects model in order to determine the performance of first-trimester ultrasound in the detection of major cardiac abnormalities overall and of individual types of cardiac abnormality. Data were analyzed separately for high-risk and non-high-risk populations. Preplanned secondary analyses were conducted in order to assess factors that may impact screening performance, including the imaging protocol used for cardiac assessment (including the use of color-flow Doppler), ultrasound modality, year of publication and the index of sonographer suspicion at the time of the scan. Risk of bias and quality assessment were undertaken for all included studies using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool.

RESULTS

The electronic search yielded 4108 citations. Following review of titles and abstracts, 223 publications underwent full-text review, of which 63 studies, reporting on 328 262 fetuses, were selected for inclusion in the meta-analysis. In the non-high-risk population (45 studies, 306 872 fetuses), 1445 major cardiac anomalies were identified (prevalence, 0.41% (95% CI, 0.39-0.43%)). Of these, 767 were detected on first-trimester ultrasound examination of the heart and 678 were not detected. First-trimester ultrasound had a pooled sensitivity of 55.80% (95% CI, 45.87-65.50%), specificity of 99.98% (95% CI, 99.97-99.99%) and positive predictive value of 94.85% (95% CI, 91.63-97.32%) in the non-high-risk population. The cases diagnosed in the first trimester represented 63.67% (95% CI, 54.35-72.49%) of all antenatally diagnosed major cardiac abnormalities in the non-high-risk population. In the high-risk population (18 studies, 21 390 fetuses), 480 major cardiac anomalies were identified (prevalence, 1.36% (95% CI, 1.20-1.52%)). Of these, 338 were detected on first-trimester ultrasound examination and 142 were not detected. First-trimester ultrasound had a pooled sensitivity of 67.74% (95% CI, 55.25-79.06%), specificity of 99.75% (95% CI, 99.47-99.92%) and positive predictive value of 94.22% (95% CI, 90.22-97.22%) in the high-risk population. The cases diagnosed in the first trimester represented 79.86% (95% CI, 69.89-88.25%) of all antenatally diagnosed major cardiac abnormalities in the high-risk population. The imaging protocol used for examination was found to have an important impact on screening performance in both populations (P < 0.0001), with a significantly higher detection rate observed in studies using at least one outflow-tract view or color-flow Doppler imaging (both P < 0.0001). Different types of cardiac anomaly were not equally amenable to detection on first-trimester ultrasound.

CONCLUSIONS

First-trimester ultrasound examination of the fetal heart allows identification of over half of fetuses affected by major cardiac pathology. Future first-trimester screening programs should follow structured anatomical assessment protocols and consider the introduction of outflow-tract views and color-flow Doppler imaging, as this would improve detection rates of fetal cardiac pathology. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Impact of Socioeconomic Status, Race and Ethnicity, and Geography on Prenatal Detection of Hypoplastic Left Heart Syndrome and Transposition of the Great Arteries

BACKGROUND

Prenatal detection (PND) has benefits for infants with hypoplastic left heart syndrome (HLHS) and transposition of the great arteries (TGA), but associations between sociodemographic and geographic factors with PND have not been sufficiently explored. This study evaluated whether socioeconomic quartile (SEQ), public insurance, race and ethnicity, rural residence, and distance of residence (distance and driving time from a cardiac surgical center) are associated with the PND or timing of PND, with a secondary aim to analyze differences between the United States and Canada.

METHODS

In this retrospective cohort study, fetuses and infants <2 months of age with HLHS or TGA admitted between 2012 and 2016 to participating Fetal Heart Society Research Collaborative institutions in the United States and Canada were included. SEQ, rural residence, and distance of residence were derived using maternal census tract from the maternal address at first visit. Subjects were assigned a SEQ z score using the neighborhood summary score or Canadian Chan index and separated into quartiles. Insurance type and self-reported race and ethnicity were obtained from medical charts. We evaluated associations among SEQ, insurance type, race and ethnicity, rural residence, and distance of residence with PND of HLHS and TGA (aggregate and individually) using bivariate analysis with adjusted associations for confounding variables and cluster analysis for centers.

RESULTS

Data on 1862 subjects (HLHS: n=1171, 92% PND; TGA: n=691, 58% PND) were submitted by 21 centers (19 in the United States). In the United States, lower SEQ was associated with lower PND in HLHS and TGA, with the strongest association in the lower SEQ of pregnancies with fetal TGA (quartile 1, 0.78 [95% CI, 0.64-0.85], quartile 2, 0.77 [95% CI, 0.64-0.93], quartile 3, 0.83 [95% CI, 0.69-1.00], quartile 4, reference). Hispanic ethnicity (relative risk, 0.85 [95% CI, 0.72-0.99]) and rural residence (relative risk, 0.78 [95% CI, 0.64-0.95]) were also associated with lower PND in TGA. Lower SEQ was associated with later PND overall; in the United States, rural residence and public insurance were also associated with later PND.

CONCLUSIONS

We demonstrate that lower SEQ, Hispanic ethnicity, and rural residence are associated with decreased PND for TGA, with lower SEQ also being associated with decreased PND for HLHS. Future work to increase PND should be considered in these specific populations.

Is Fetal Intelligent Navigation Echocardiography Helpful in Screening for d-Transposition of the Great Arteries?

OBJECTIVES

To evaluate the performance of fetal intelligent navigation echocardiography (FINE) applied to spatiotemporal image correlation (STIC) volumes in generating 3 specific abnormal cardiac views (left ventricular outflow tract, right ventricular outflow tract, and 3-vessel and trachea) used to screen for d-transposition of the great arteries (d-TGA).

METHODS

In this prospective study, 1 or more STIC volumes were obtained from the 4-chamber view in 34 second- and third-trimester fetuses with d-TGA. Each appropriate STIC volume was evaluated by STICLoop (Samsung Medison, Seoul, Korea) before applying the FINE method. One optimal volume per fetus was selected by observers. The visualization rates of the 3 specific abnormal cardiac views of d-TGA and their diagnostic elements were calculated, and the reliability between 2 observers was verified by the intraclass correlation coefficient.

RESULTS

Fetal intelligent navigation echocardiography applied to STIC volume data sets of fetuses with d-TGA successfully generated the 3 specific abnormal cardiac views in the following manner for 2 observers: 75.0% (n = 21) for the left ventricular outflow tract, 89.2% (n = 25) for the right ventricular outflow tract, and 85.7% (n = 24) for the 3-vessel and trachea view. Twenty-four (85.7%) of the STIC volume data sets showed 2 or 3 of the abnormal cardiac views. The interobserver intraclass correlation coefficients between the 2 observers ranged from 0.842 to 1.000 (95% confidence interval), indicating almost perfect reliability for the 2 observers.

CONCLUSIONS

In cases of d-TGA, the FINE method has a high success rate in generating 3 specific abnormal cardiac views and therefore can be performed to screen for this congenital defect.

Detailed Echocardiographic Measurements of Individual Chamber in a Chinese Cohort of Hypoplastic Left Heart Syndrome and Comparison with Normal Fetuses via Z-score Modeling

Hypoplastic left heart syndrome (HLHS) is a rare, but exceptionally serious, congenital heart defect. We aimed to explore the best-fitted Z-score models for individual chamber dimension and to draw a comparison between fetuses with HLHS and the normal Chinese cohort. We made measurements of 1674 healthy fetuses and 79 fetuses with HLHS, undertaking echocardiography. Normal fetal cardiovascular Z-score formulae were established by curve-fitting with 5 algorithmic functions and weighted regression of absolute residuals. Classic linear models were fitted for left ventricular diameter against gestational age, and log-transformed linear-power models-were statistically better for left ventricular length, diameter of left atrium and ascending aorta. Fetuses with HLHS manifested significantly lower Z-score means (≤3.5) for these 4 parameters and the vast majority (∼90%) lay beyond -2. Overall, cardiovascular Z-score equations were reliably constructed in a larger Chinese cohort, and their application should benefit evaluation and diagnosis of HLHS.

Population trends in prenatal detection of transposition of great arteries: impact of obstetric screening ultrasound guidelines

OBJECTIVES

Dextro-transposition of the great arteries (d-TGA) is one of the most common critical neonatal heart defects, with a low detection rate antenatally. We sought to evaluate trends in the prenatal detection of d-TGA with or without ventricular septal defect (VSD) in Alberta over the past 13 years, examining the potential impact of ultrasound guidelines incorporating screening of cardiac outflow tracts, updated in 2009-2010 and in 2013, and factors affecting detection of the condition.

METHODS

All fetuses and neonates with d-TGA, with or without VSD, encountered between 2003 and 2015 in the province of Alberta, were identified retrospectively. Clinical records including obstetric ultrasound reports were reviewed. Pregnancy outcome, common referral indications and associated maternal and fetal pathology in affected pregnancies were assessed.

RESULTS

From 2003 to 2015, 127 cases with d-TGA were encountered in Alberta, of which 47 (37%) were detected prenatally. Prenatal detection improved over the study period, from 14% in 2003-2010, to 50% in 2011-2013, and to 77% in 2014-2015. Of the 47 fetuses with a prenatal diagnosis of d-TGA, an indication for fetal echocardiography included abnormal or poorly visualized cardiac outflows with normal four-chamber view in 46 (98%). Comorbidities were identified in 12 mothers, only five of which represented an additional reason for fetal echocardiography referral, and four fetuses had extracardiac pathology.

CONCLUSION

Substantial improvement in the prenatal detection of d-TGA has been observed in Alberta over the past few years, owing to improved screening of cardiac outflow tracts on routine obstetric ultrasound examination in otherwise healthy pregnancies, and has been temporally associated with updated obstetric ultrasound guidelines suggesting that these contributed to optimized screening of affected pregnancies. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

[Relevance of the detection of complex congenital heart disease by screening with pulse oximetry in apparently healthy newborns in health establishments]

A review is presented of data published in medical literature related to the screening used for the early detection of complex congenital heart disease in apparently healthy newborns in several cities of the world, including those reported in Mexico. The screening was performed due to the knowledge of the pathophysiology of indirect hypoxia data, observation of differential cyanosis and the consequent difference in the values of pre- and post-ductal pulse oximetry derived from the ductal and/or atrial septal defect dependence of several severe congenital heart diseases. Multicentre research studies have also been carried out on a massive scale, thus justifying the usefulness of the practice for its daily implementation and at international level. Additionally, legislative topics are cited in our country as part of the efforts to establish the mandatory nature of the screening throughout the Mexican Republic.

Pulse oximetry screening in newborns to enhance detection of critical congenital heart disease

Pulse oximetry screening is safe, noninvasive, easy to perform and proven to enhance detection of critical congenital heart disease in newborns. However, this test has yet to be adopted as routine practice in Canada. The present practice point highlights essential details and recommendations for screening, which research has shown to be highly specific, with low false-positive rates. Optimal screening for critical congenital heart disease should include prenatal ultrasound, physical examination and pulse oximetry screening. Screening should be performed between 24 hours and 36 hours postbirth, using the infant's right hand and either foot to minimize false-positive results. Newborns with abnormal results should undergo a thorough evaluation by the most responsible health care provider. When a cardiac diagnosis cannot be excluded, referral to a paediatric cardiologist for consultation and echocardiogram is advised.

Systematic review and meta-analysis of the performance of second-trimester screening for prenatal detection of congenital heart defects

BACKGROUND

The prenatal detection rate of congenital heart defects (CHDs) is increasing, but reported rates vary.

OBJECTIVES

To determine the performance of the second-trimester anomaly scan to detect CHD.

SEARCH STRATEGY

PubMed and Embase were searched for relevant studies in any language from inception to February 3, 2017. The search terms included "prenatal diagnosis" or "pregnancy," "cardiovascular diseases" or "cardiac defects," "congenital," and "specificity," or "sensitivity," or "cohort study."

SELECTION CRITERIA

Cohort studies assessing the detection rate of CHD during population-based prenatal screening from 1995 were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Data were collected from identified studies; authors were approached for additional data when necessary. A review and meta-analysis were performed. When possible, separate analyses were undertaken for isolated CHD cases.

MAIN RESULTS

Meta-analysis of seven studies showed the pooled detection rate of CHD in unselected populations as 45.1% (95% confidence interval 33.5%-57.0%). However, the rate of detection of univentricular defects and heterotaxy was above 85%. Similar rates were found among cases of isolated CHD.

CONCLUSIONS

Prenatal detection showed a strong correlation with CHD severity. The detection of conotruncal anomalies needs to improve. A thoroughly organized screening program will be essential to achieve a higher detection rate.

A Combined Independent Source Separation and Quality Index Optimization Method for Fetal ECG Extraction from Abdominal Maternal Leads

The non-invasive fetal electrocardiogram (fECG) technique has recently received considerable interest in monitoring fetal health. The aim of our paper is to propose a novel fECG algorithm based on the combination of the criteria of independent source separation and of a quality index optimization (ICAQIO-based). The algorithm was compared with two methods applying the two different criteria independently—the ICA-based and the QIO-based methods—which were previously developed by our group. All three methods were tested on the recently implemented Fetal ECG Synthetic Database (FECGSYNDB). Moreover, the performance of the algorithm was tested on real data from the PhysioNet fetal ECG Challenge 2013 Database. The proposed combined method outperformed the other two algorithms on the FECGSYNDB (ICAQIO-based: 98.78%, QIO-based: 97.77%, ICA-based: 97.61%). Significant differences were obtained in particular in the conditions when uterine contractions and maternal and fetal ectopic beats occurred. On the real data, all three methods obtained very high performances, with the QIO-based method proving slightly better than the other two (ICAQIO-based: 99.38%, QIO-based: 99.76%, ICA-based: 99.37%). The findings from this study suggest that the proposed method could potentially be applied as a novel algorithm for accurate extraction of fECG, especially in critical recording conditions.

Sonographer-Identified Barriers and Facilitators to Prenatal Screening for Congenital Heart Disease

Background: Fetal ultrasound screening for congenital heart disease has high detection rates in efficacy studies but not in practice. We investigated sonographers’ perspectives on barriers to screening and their association with intermediate measures of cardiac imaging. Methods: Barriers to fetal heart screening were identified in focus groups with obstetric sonographers. A web-based survey measured reported barriers and sonographers’ ability to interpret fetal heart screening images. Generalized linear random effect models assessed associations between barriers and image interpretation. Results: Four themes were identified: intrinsic barriers (self-efficacy), external barriers (time), informational needs, and provider and patient expectations. Among 224 sonographers surveyed, an average of 77.6% of fetal heart images were interpreted correctly. Perceptions about self-efficacy ( P = .03) and ease of performing imaging ( P = .01) were associated with accuracy of image interpretation. Conclusions: Several sonographer-identified barriers associated with image interpretation may be novel targets for improving prenatal detection of congenital heart disease.

Canadian Cardiovascular Society/Canadian Pediatric Cardiology Association Position Statement on Pulse Oximetry Screening in Newborns to Enhance Detection of Critical Congenital Heart Disease

Congenital heart disease is the most common congenital malformation and approximately 3 in 1000 newborns have critical congenital heart disease (CCHD). Timely diagnosis affects morbidity, mortality, and disability, and newborn pulse oximetry screening has been studied to enhance detection of CCHD. In this position statement we present an evaluation of the literature for pulse oximetry screening. Current detection strategies including prenatal ultrasound examination and newborn physical examination are limited by low diagnostic sensitivity. Pulse oximetry screening is safe, noninvasive, easy to perform, and widely available with a high specificity (99.9%) and moderately high sensitivity (76.5%). When an abnormal saturation is obtained, the likelihood of having CCHD is 5.5 times greater than when a normal result is obtained. The use of pulse oximetry combined with current strategies has shown sensitivities of up to 92% for detecting CCHD. False positive results can be minimized by screening after 24 hours, and testing the right hand and either foot might further increase sensitivity. Newborns with abnormal screening results should undergo a comprehensive assessment and echocardiography performed if a cardiac cause cannot be excluded. Screening has been studied to be cost neutral to cost effective. We recommend that pulse oximetry screening should be routinely performed in all healthy newborns to enhance the detection of CCHD in Canada.

Normal ranges for fetal electrocardiogram values for the healthy fetus of 18-24 weeks of gestation: a prospective cohort study

Background

The fetal anomaly ultrasound only detects 65 to 81 % of the patients with congenital heart disease, making it the most common structural fetal anomaly of which a significant part is missed during prenatal life. Therefore, we need a reliable non-invasive diagnostic method which improves the predictive value for congenital heart diseases early in pregnancy. Fetal electrocardiography could be this desired diagnostic method. There are multiple technical challenges to overcome in the conduction of the fetal electrocardiogram. In addition, interpretation is difficult due to the organisation of the fetal circulation in utero. We want to establish the normal ranges and values of the fetal electrocardiogram parameters in healthy fetuses of 18 to 24 weeks of gestation.

Methods/Design

Women with an uneventful singleton pregnancy between 18 and 24 weeks of gestation are asked to participate in this prospective cohort study. A certified and experienced sonographist performs the fetal anomaly scan. Subsequently, a fetal electrocardiogram recording is performed using dedicated signal processing methods. Measurements are performed at two institutes. We will include 300 participants to determine the normal values and 95 % confidence intervals of the fetal electrocardiogram parameters in a healthy fetus. We will evaluate the fetal heart rate, segment intervals, normalised amplitude and the fetal heart axis. Three months postpartum, we will evaluate if a newborn is healthy through a questionnaire.

Discussion

Fetal electrocardiography could be a promising tool in the screening program for congenital heart diseases. The electrocardiogram is a depiction of the intimate relationship between the cardiac nerve conduction pathways and the structural morphology of the fetal heart, and therefore particularly suitable for the detection of secondary effects due to a congenital heart disease (hypotrophy, hypertrophy and conduction interruption).

A systematic review of prenatal screening for congenital heart disease by fetal electrocardiography

BACKGROUND

Congenital heart disease (CHD) is the most common severe congenital anomaly worldwide. Diagnosis early in pregnancy is important, but the detection rate by two-dimensional ultrasonography is only 65%-81%.

OBJECTIVES

To evaluate existing data on CHD and noninvasive abdominal fetal electrocardiography (ECG).

SEARCH STRATEGY

A systematic review was performed through a search of the Cochrane Library, PubMed, and Embase for studies published up to April 2016 using the terms "congenital heart disease," "fetal electrocardiogram," and other similar keywords.

SELECTION CRITERIA

Primary articles that described changes in fetal ECG among fetuses with CHD published in English were included.

DATA COLLECTION AND ANALYSIS

Outcomes of interest were changes in fetal ECG parameters observed for fetuses with congenital heart disease. Findings were reported descriptively.

MAIN RESULTS

Only five studies described changes observed in the fetal electrocardiogram for fetuses with CHD, including heart rate, heart rate variability, and PR, QRS, and QT intervals. Fetal ECG reflects the intimate relationship between the cardiac nerve conduction system and the structural morphology of the heart. It seems particularly helpful in detecting the electrophysiological effects of cardiac anatomic defects (e.g. hypotrophy, hypertrophy, and conduction interruption).

CONCLUSIONS

Fetal ECG might be a promising clinical tool to complement ultrasonography in the screening program for CHD.

The Application of an Anatomical Database for Fetal Congenital Heart Disease

Background:

Fetal congenital heart anomalies are the most common congenital anomalies in live births. Fetal echocardiography (FECG) is the only prenatal diagnostic approach used to detect fetal congenital heart disease (CHD). FECG is not widely used, and the antenatal diagnosis rate of CHD varies considerably. Thus, mastering the anatomical characteristics of different kinds of CHD is critical for ultrasound physicians to improve FECG technology. The aim of this study is to investigate the applications of a fetal CHD anatomic database in FECG teaching and training program.

Methods:

We evaluated 60 transverse section databases including 27 types of fetal CHD built in the Prenatal Diagnosis Center in Peking University People's Hospital. Each original database contained 400–700 cross-sectional digital images with a resolution of 3744 pixels × 5616 pixels. We imported the database into Amira 5.3.1 (Australia Visage Imaging Company, Australia) three-dimensional (3D) software. The database functions use a series of 3D software visual operations. The features of the fetal CHD anatomical database were analyzed to determine its applications in FECG continuing education and training.

Results:

The database was rebuilt using the 3D software. The original and rebuilt databases can be displayed dynamically, continuously, and synchronically and can be rotated at arbitrary angles. The sections from the dynamic displays and rotating angles are consistent with the sections in FECG. The database successfully reproduced the anatomic structures and spatial relationship features of different fetal CHDs. We established a fetal CHD anatomy training database and a standardized training database for FECG. Ultrasound physicians and students can learn the anatomical features of fetal CHD and FECG through either centralized training or distance education.

Conclusions:

The database of fetal CHD successfully reproduced the anatomic structures and spatial relationship of different kinds of fetal CHD. This database can be widely used in anatomy and FECG teaching and training.

Prenatal Counseling and Care for Single-Ventricle Heart Disease: One Center’s Model for Care

Advances in prenatal imaging allow early detection of single-ventricle congenital heart disease, which may enhance prenatal care and maximize care options and decision making. Boston Children’s Hospital’s Advanced Fetal Care Center and fetal cardiology program provide prenatal counseling and care for single-ventricle congenital heart disease. Key points for optimal prenatal counseling and education include explanation of the diagnosis, delivery, the first surgery, cardiac neurodevelopmental issues, feeding and growth issues, quality of life and long-term care, family stressors, and fetal cardiac intervention. Such counseling and education help families make the difficult decisions required in this situation.

Variation in Prenatal Diagnosis of Congenital Heart Disease in Infants

BACKGROUND AND OBJECTIVE

Prenatal diagnosis allows improved perioperative outcomes for fetuses with certain forms of congenital heart disease (CHD). Variability in prenatal diagnosis has been demonstrated in other countries, leading to efforts to improve fetal imaging protocols and access to care, but has not been examined across the United States. The objective was to evaluate national variation in prenatal detection across geographic region and defect type in neonates and infants with CHD undergoing heart surgery.

METHODS

Cardiovascular operations performed in patients ≤6 months of age in the United States and included in the Society of Thoracic Surgeons Congenital Heart Surgery Database (2006-2012) were eligible for inclusion. Centers with >15% missing prenatal diagnosis data were excluded from the study. Prenatal diagnosis rates were compared across geographic location of residence and defect type using the χ(2) test.

RESULTS

Overall, the study included 31,374 patients from 91 Society of Thoracic Surgeons Congenital Heart Surgery Database participating centers across the United States. Prenatal detection occurred in 34% and increased every year, from 26% (2006) to 42% (2012). There was significant geographic variation in rates of prenatal diagnosis across states (range 11.8%-53.4%, P < .0001). Significant variability by defect type was also observed, with higher rates for lesions identifiable on 4-chamber view than for those requiring outflow tract visualization (57% vs 32%, P < .0001).

CONCLUSIONS

Rates of prenatal CHD detection in the United States remain low for patients undergoing surgical intervention, with significant variability between states and across defect type. Additional studies are needed to identify reasons for this variation and the potential impact on patient outcomes.

Prenatal diagnosis of transposition of the great arteries over a 20-year period: improved but imperfect

OBJECTIVE

To evaluate temporal trends in the prenatal diagnosis of transposition of the great arteries with intact ventricular septum (TGA/IVS) and its impact on neonatal morbidity and mortality.

METHODS

We included in this study cohort newborns with TGA/IVS who were referred for surgical management to our center over a 20-year period (1992-2011). The study period was divided into five 4-year periods and the primary outcome was rate of prenatal diagnosis. Secondary outcomes included neonatal preoperative status and perioperative survival.

RESULTS

Of the 340 patients with TGA/IVS, 81 (23.8%) had a prenatal diagnosis. The rate of prenatal diagnosis increased over the study period, from 6% in 1992-1995 to 41% in 2008-2011 (P < 0.001). Compared to patients with a postnatal diagnosis, balloon atrial septostomy (BAS) was performed earlier in patients with a prenatal diagnosis (0 days after delivery vs 1 day after delivery, respectively; P < 0.001) and fewer prenatally diagnosed neonates required mechanical ventilation (55.6% vs 68.0%; P = 0.03). Between patients with a prenatal or postnatal diagnosis of TGA/IVS, there were no statistically significant differences in the incidence of preoperative acidosis (16.0% vs 25.5%; P = 0.1), need for preoperative extracorporeal membrane oxygenation (2.5% vs 2.7%; P = 1.0) or mortality (one preoperative and no postoperative deaths among prenatally diagnosed patients compared with four preoperative and six postoperative deaths among postnatally diagnosed patients).

CONCLUSIONS

The prenatal detection rate of TGA/IVS has improved but still remains below 50%, suggesting the need for strategies to increase detection rates. The mortality rate was not statistically significantly different between prenatally and postnatally diagnosed patients, however, there were significant preoperative differences with regard to earlier BAS and fewer neonates that required mechanical ventilation. Ongoing work is required to ascertain whether prenatal diagnosis confers long-term benefits.

Pediatric prenatal diagnosis of congenital heart disease

PURPOSE OF REVIEW

Fetal cardiology is a rapidly evolving field. Imaging technology continues to advance as do approaches to in-utero interventions and care of the critically ill neonate, with even greater demand for improvement in prenatal diagnosis of congenital heart disease (CHD) and arrhythmias.

RECENT FINDINGS

Reviewing the advances in prenatal diagnosis of CHD in such a rapidly developing field is a broad topic. Therefore, we have chosen to focus this review of recent literature on challenges in prenatal detection of CHD, challenges in prenatal counseling, advances in fetal arrhythmia diagnosis, and potential benefits to patients with CHD who are identified prenatally.

SUMMARY

As methods and tools to diagnose and manage CHD and arrhythmias in utero continue to improve, future generations will hopefully see a reduction in both prenatal and neonatal morbidity and mortality. Prenatal diagnosis can and should be used to optimize location and timing of delivery and postnatal interventions.