Influence of ultrasonographers training on prenatal diagnosis of congenital heart diseases: a 12-year population-based study

High Heterogeneity in Prenatal Detection of Severe Congenital Heart Defects Among Physicians, Hospitals and Regions in Quebec

BACKGROUND

Prenatal detection rates (PDRs) of severe congenital heart defects (SCHDs) are often presented as regional and national aggregates, which might hide significant heterogeneity in PDRs among physicians, hospitals, and regions. The objective was to quantify the variability in the sensitivity of second-trimester ultrasound examination (U/S) to detect SCHDs, and to identify at which level this variability was the greatest.

METHODS

This was a retrospective observational cohort of all pregnancy-child dyads with SCHDs in Quebec between 2007 and 2015. We matched the clinical data from the hospitals with the administrative data from the health care system. The variability at each level was estimated using multilevel models by calculating intraclass correlation coefficients.

RESULTS

Of 1274 SCHD, 697 were diagnosed prenatally following a referral for a suspected cardiac anomaly on U/S, yielding a sensitivity of 54.7% (95% confidence interval [CI], 52.0%-57.4%). Significant heterogeneity was observed among physicians, hospitals, and regions with the greatest heterogeneity among physicians. The U/S sensitivities in the lowest quartile for physicians, hospitals, and regions were 27.4%, 29.0%, and 39.8%, and those in the highest quartile were 87.3%, 70.1%, and 62.9%, respectively. The mean difference of sensitivity between the lowest and highest quartiles was 59.9% (95% CI, 51.7-68.1) for physicians, and 41.1% (95% CI, 30.3-51.9) for hospitals. The intraclass correlation coefficients at the physician level indicated the greatest heterogeneity among physicians (intrahospital).

CONCLUSIONS

There was considerable heterogeneity in PDRs between physicians and hospitals. The driver of the heterogeneity seemed to be at the physician level, with higher interphysician variability. Any measures of improvement should be directed to the physician level.

Physician Barriers and Facilitators for Screening for Congenital Heart Disease With Routine Obstetric Ultrasound: A National United States Survey

OBJECTIVES

Prenatal detection of congenital heart disease with obstetric screening remains at less than 50% in most population studies, far from what is thought to be achievable. We sought to identify barriers/facilitators for screening from the perspective of interpreting physicians and to understand how these barriers/facilitators may be associated with interpretation of screening images.

METHODS

Our mixed-methods studies included 4 focus groups in centers across the United States with obstetric, maternal-fetal medicine, and radiology providers who interpreted obstetric ultrasound studies. Themes around barriers/facilitators for fetal heart screening were coded from transcripts. A national Web-based survey was then conducted, which quantitatively measured reported barriers/facilitators and measured physicians' ability to interpret fetal heart-screening images. Multivariable generalized linear random-effect models assessed the association between barriers/facilitators and the accuracy of image interpretation at the image level.

RESULTS

Three main themes were identified in the focus groups: intrinsic barriers (ie, comfort with screening), external barriers (ie, lack of feedback), and organizational barriers (ie, study volumes). Among 190 physician respondents, 104 interpreted ultrasound studies. Perceptions of barriers varied by practice setting, with nontertiary providers having lower self-efficacy and perceived usefulness of cardiac screening. Facilitators associated with the odds of accurate interpretation of screening images were knowledge (odds ratio, 2.54; P = .002) and the volume of scans per week (odds ratio, 1.01 for every additional scan; P = .04).

CONCLUSIONS

Some of the main barriers to cardiac screening identified and prioritized by physicians across the United States were knowledge of screening and minimal volumes of scans. Targeting these barriers will aid in improving prenatal detection of congenital heart disease.

Why are congenital heart defects being missed?

OBJECTIVE

Congenital heart defects (CHD) are still missed frequently in prenatal screening programs, which can result in severe morbidity or even death. The aim of this study was to evaluate the quality of fetal heart images, obtained during the second-trimester standard anomaly scan (SAS) in cases of CHD, to explore factors associated with a missed prenatal diagnosis.

METHODS

In this case-control study, all cases of a fetus born with isolated severe CHD in the Northwestern region of The Netherlands, between 2015 and 2016, were extracted from the PRECOR registry. Severe CHD was defined as need for surgical repair in the first year postpartum. Each cardiac view (four-chamber view (4CV), three-vessel (3V) view and left and right ventricular outflow tract (LVOT, RVOT) views) obtained during the SAS was scored for technical correctness on a scale of 0 to 5 by two fetal echocardiography experts, blinded to the diagnosis of CHD and whether it was detected prenatally. Quality parameters of the cardiac examination were compared between cases in which CHD was detected and those in which it was missed on the SAS. Regression analysis was used to assess the association of sonographer experience and of screening-center experience with the cardiac examination quality score.

RESULTS

A total of 114 cases of isolated severe CHD at birth were analyzed, of which 58 (50.9%) were missed and 56 (49.1%) were detected on the SAS. The defects comprised transposition of the great arteries (17%), aortic coarctation (16%), tetralogy of Fallot (10%), atrioventricular septal defect (6%), aortic valve stenosis (5%), ventricular septal defect (18%) and other defects (28%). No differences were found in fetal position, obstetric history, maternal age or body mass index (BMI) or gestational age at examination between missed and detected cases. Ninety-two cases had available cardiac images from the SAS. Compared with the detected group, the missed group had significantly lower cardiac examination quality scores (adequate score (≥ 12) in 32% vs 64%; P = 0.002), rate of proper use of magnification (58% vs 84%; P = 0.01) and quality scores for each individual cardiac plane (4CV (2.7 vs 3.9; P < 0.001), 3V view (3.0 vs 3.8; P = 0.02), LVOT view (1.9 vs 3.3; P < 0.001) and RVOT view (1.9 vs 3.3; P < 0.001)). In 49% of missed cases, the lack of detection was due to poor adaptational skills resulting in inadequate images in which the CHD was not clearly visible; in 31%, the images showed an abnormality (mainly septal defects and aortic arch anomalies) which had not been recognized at the time of the scan; and, in 20%, the cardiac planes had been obtained properly but showed normal anatomy. Multivariate regression analysis showed that the volume of SAS performed per year by each sonographer was associated significantly with quality score of the cardiac examination.

CONCLUSIONS

A lack of adaptational skills when performing the SAS, as opposed to circumstantial factors such as BMI or fetal position, appears to play an important role in failure to detect CHD prenatally. The quality of the cardiac views was inadequate significantly more often in undetected compared with detected cases. Despite adequate quality of the images, CHD was not recognized in 31% of cases. A high volume of SAS performed by each sonographer in a large ultrasound center contributes significantly to prenatal detection. In 20% of undetected cases, CHD was not visible even though the quality of the images was good. © 2019 Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Risk Stratification of Fetal Cardiac Anomalies in an Underserved Population Using Telecardiology

OBJECTIVE

To evaluate a fetal telecardiology program in a medically underserved area.

METHODS

We conducted a prospective case series of pregnant women at 18-38 weeks of gestation with risk factors for fetal congenital heart disease. Obstetric ultrasonographers performed fetal echocardiograms (local site) that were read in real time. The results were given to the mother by a fetal cardiologist at a children's hospital 243 miles and two mountain passes away (distant site). We evaluated the fetal telecardiology program in five domains: 1) education of obstetric ultrasonographers before initiation of telecardiology services, 2) process and efficiency, 3) patient satisfaction, 4) economic effects, and 5) accuracy of cardiac diagnosis and success of risk stratification.

RESULTS

The program was initiated on November 12, 2015, and here we describe its first 37 months. Over the initial training period of 3 months and about 70 examinations, obstetric ultrasonographers improved their identification of fetal congenital heart disease. Telecardiology was performed once a week and also for suspected fetal congenital heart disease or arrhythmia outside clinic hours, for a total of 455 examinations. All mothers preferred having their fetal cardiac evaluations performed locally as opposed to traveling to the distant center. The estimated cost to parents for fetal cardiac evaluation at the distant center was nine times greater than that of telecardiology ($581 vs $61). Congenital heart disease or arrhythmia was diagnosed in 28 and 15 fetuses, respectively; there was one false-negative result. All fetuses were correctly risk-stratified with respect to delivery location.

CONCLUSIONS

Neither diagnostic quality nor patient satisfaction were sacrificed with telecardiology. The program was feasible, empowered the local health care providers and ultrasonographers, offered strong economic advantages to families, and offered the benefit of timely standard-of-care, face-to-face consultation without travel. Based on the success of this program, further studies are warranted to assess its replicability.

Echocardiographic and pathomorphological features in fetuses with ductal-dependent congenital heart diseases

OBJECTIVE

To individually analyze echocardiographic features in fetuses with ductal-dependent congenital heart diseases (DDCHD) and to verify the anatomical characteristics corresponding to the echocardiogram scan views.

BACKGROUND

Ductal-dependent congenital heart diseases depends on the ductus arteriosus (DA) remaining open to maintain suitable pulmonary or systemic circulation after birth. An accurate diagnosis using prenatal echocardiography has important clinical significance in evaluating disease prognosis and ensuring timely treatment.

METHODS

Fetuses were followed in the prenatal and postpartum periods via echocardiography. The results of postpartum echocardiography or autopsy specimens were compared with the prenatal echocardiography findings.

RESULTS

One hundred and eight fetuses displayed various types of DDCHD including 66 fetuses with ductal-dependent pulmonary circulation, and 42 fetuses with ductal-dependent systemic circulation. Prenatal echocardiography revealed the typical characteristics of no forward flow signal from right ventricular outflow tract to the pulmonary trunk proximally and a reverse flow in the DA in most fetuses for ductal-dependent pulmonary circulation, a reverse flow in the transverse aortic arch for aorta atresia, and a loss of continuity between aortic arch and descending aorta for interruption of the aortic arch (IAA). All 108 fetuses displayed various types of complex CHD, including right ventricular dysplasia with pulmonary atresia (PA), severe Ebstein anomaly, double outlet right ventricle with PA, tetralogy of fallot with PA, single ventricle with PA or aorta atresia, hypoplastic left heart syndrome, and IAA.

CONCLUSIONS

The identification of reverse flow in the aortic arch or DA aids in the subsequent accurate diagnosis of DDCHD associated with complex malformation of the heart.

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.

Automated annotation and quantitative description of ultrasound videos of the fetal heart

Interpretation of ultrasound videos of the fetal heart is crucial for the antenatal diagnosis of congenital heart disease (CHD). We believe that automated image analysis techniques could make an important contribution towards improving CHD detection rates. However, to our knowledge, no previous work has been done in this area. With this goal in mind, this paper presents a framework for tracking the key variables that describe the content of each frame of freehand 2D ultrasound scanning videos of the healthy fetal heart. This represents an important first step towards developing tools that can assist with CHD detection in abnormal cases. We argue that it is natural to approach this as a sequential Bayesian filtering problem, due to the strong prior model we have of the underlying anatomy, and the ambiguity of the appearance of structures in ultrasound images. We train classification and regression forests to predict the visibility, location and orientation of the fetal heart in the image, and the viewing plane label from each frame. We also develop a novel adaptation of regression forests for circular variables to deal with the prediction of cardiac phase. Using a particle-filtering-based method to combine predictions from multiple video frames, we demonstrate how to filter this information to give a temporally consistent output at real-time speeds. We present results on a challenging dataset gathered in a real-world clinical setting and compare to expert annotations, achieving similar levels of accuracy to the levels of inter- and intra-observer variation.

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.

Impact of a standardized training program on midwives' ability to assess fetal heart anatomy by ultrasound

BACKGROUND

Studies of prenatal detection of congenital heart disease (CHD) in the UK, Italy, and Norway indicate that it should be possible to improve the prenatal detection rate of CHD in Sweden. These studies have shown that training programs, visualization of the outflow tracts and color-Doppler all can help to speed up and improve the detection rate and accuracy. We aimed to introduce a more accurate standardized fetal cardiac ultrasound screening protocol in Sweden.

METHODS

A novel pedagogical model for training midwives in standardized cardiac imaging was developed, a model using a think-aloud analysis during a pre- and post-course test and a subsequent group reflection. The self-estimated difficulties and knowledge gaps of two experienced and two beginner midwives were identified. A two-day course with mixed lectures, demonstrations and hands-on sessions was followed by a feedback session three months later consisting of an interview and check-up. The long-term effects were tested two years later.

RESULTS

At the post-course test the self-assessed uncertainty was lower than at the pre-course test. The qualitative evaluation showed that the color Doppler images were difficult to interpret, but the training seems to have improved their ability to use the new technique. The ability to perform the method remained at the new level at follow-up both three months and two years later.

CONCLUSIONS

Our results indicate that by implementing new imaging modalities and providing hands-on training, uncertainty can be reduced and examination time decreased, but they also show that continuous on-site training with clinical and technical back-up is important.

Transposition of the great arteries: factors influencing prenatal diagnosis

OBJECTIVE

The objective of this study is to highlight the factors that may affect prenatal diagnosis of transposition of the great arteries (TGA) in order to improve it.

METHODS

This is a retrospective study performed between 2004 and 2009 in the maternity units from North of France. We identified a total of 68 cases of TGA (isolated or associated with only VSD or coarctation of aorta), of which 32 (47.1%) had prenatal diagnosis (PND+) and 36 did not (PND-). Maternal characteristics and ultrasound factors were studied in relation to PND.

RESULTS

Maternal weight and body mass index were significantly higher in the PND- group (70.4 kg and 26.5 kg/m(2) vs 63.6 kg and 23.6 kg/m(2) , respectively). Maternal obesity (body mass index >30) was significantly more frequent in the PND- group (27.8% vs 12.5%). More than a quarter of TGA (28.1%) were diagnosed during the third trimester.

CONCLUSION

Obesity is the main cause of missed PND of TGA. Obese patients with suboptimal prenatal scans may benefit from reassessment of fetal cardiac anatomy and/or from referral for fetal echocardiography.

A fetal telecardiology service: patient preference and socio-economic factors

OBJECTIVE

The aims of this study were to evaluate patients' opinions on a fetal cardiology telemedicine service compared with usual outpatient care, the effect of the telemedicine consultation on maternal anxiety and its impact on travel times and time absent from work.

METHODS

Prospective study over 20 months. Eligible patients attended for routine anomaly scan followed by fetal echocardiogram transmitted to the regional centre with live guidance by a fetal cardiologist, followed by parental counselling. All patients were offered a fetal cardiology appointment at the regional centre. Structured questionnaires assessing maternal satisfaction, travel times/days off and anxiety scores completed at time of both fetal echocardiograms.

RESULTS

Sixty-seven patients were recruited and 66 completed the study. Participants expressed very high satisfaction rates with fetal telecardiology, equivalent to face-to-face consultation. The telecardiology appointments were associated with significantly reduced travel times and days off work (p < 0.01). Expectant mothers expressed a clear inclination for a fetal cardiology appointment at the local hospital facilitated by telemedicine (p < 0.01).

CONCLUSIONS

Fetal telecardiology is highly acceptable to patients and is even preferred compared with travelling to a regional centre. There are additional socio-economic benefits that should encourage the development of remote fetal cardiology services.

Fetal cardiac screening and variation in prenatal detection rates of congenital heart disease: why bother with screening at all?

Antenatal screening for fetal cardiac abnormalities was introduced over 25 years ago, yet detection of congenital heart disease before birth remains a challenge. While experienced tertiary centers report a high level of diagnostic accuracy, with most major forms of congenital heart disease being detectable before birth, the overall detection rate remains low. Pregnancies at increased risk of having an affected baby are referred to tertiary centers for fetal ECG, but most cases of congenital heart disease will occur in low-risk pregnancies. These cases will only be detected by screening the low-risk population at the time of routine obstetric scanning. Many obstetric ultrasound units have learnt to successfully obtain, and correctly interpret, views of the heart, including the four-chamber view and outflow tract views. However, standards for doing this are not uniform, nationally or internationally, so there is a significant variation in detection rates across individual countries and between different countries. Early diagnosis of babies with lesions that can result in cardiovascular collapse and death, could improve their survival as well as reducing morbidity. In addition, detection of a cardiac abnormality during pregnancy allows time to prepare parents for the likely course of events after birth. It also facilitates detection of other abnormalities in the baby and gives parents a choice, even if the choice is difficult and unwelcome. As well as providing parents with accurate and up-to-date information regarding the their baby’s abnormality, it is vital to provide continuing support to help them deal with the problem, regardless of what decisions they make. Much work remains to establish a uniform standard for antenatal detection of cardiac abnormalities. More recent national guidelines for examining the fetal heart along with formalized auditing processes should help to achieve this, although considerable time and effort will be required, particularly with regard to the teaching and training required.

Impact of fetal echocardiography

Prenatal diagnosis of congenital heart disease is now well established for a wide range of cardiac anomalies. Diagnosis of congenital heart disease during fetal life not only identifies the cardiac lesion but may also lead to detection of associated abnormalities. This information allows a detailed discussion of the prognosis with parents. For continuing pregnancies, appropriate preparation can be made to optimize the postnatal outcome. Reduced morbidity and mortality, following antenatal diagnosis, has been reported for coarctation of the aorta, hypoplastic left heart syndrome, and transposition of the great arteries. With regard to screening policy, most affected fetuses are in the “low risk” population, emphasizing the importance of appropriate training for those who undertake such obstetric anomaly scans. As a minimum, the four chamber view of the fetal heart should be incorporated into midtrimester anomaly scans, and where feasible, views of the outflow tracts should also be included, to increase the diagnostic yield. Newer screening techniques, such as measurement of nuchal translucency, may contribute to identification of fetuses at high risk for congenital heart disease and prompt referral for detailed cardiac assessment.

Impact of a regional training program in fetal echocardiography for sonographers on the antenatal detection of major congenital heart disease

OBJECTIVES

The aims of this study were to ascertain the effect of a regional training program in fetal echocardiography for obstetric radiographers on the antenatal detection of major congenital heart disease (CHD) and to document short-term outcomes for major CHD.

METHODS

All 87 obstetric radiographers in Northern Ireland were invited to attend 2.5 days of training during a 1-year period. Data were collected before and after the training, over a 5-year study period, to assess the effect of training on the antenatal detection of CHD in the population.

RESULTS

The antenatal detection of major CHD rose significantly, from 28% (72/262) pretraining to 43% (36/84) in the year of training (P = 0.008). Antenatal diagnosis of four-chamber-view defects rose significantly (from 38% to 54%; P = 0.04), as did detection of outflow-tract-view defects (from 8% to 21%; P = 0.05). Twelve per cent (13/108) of cases died spontaneously in utero and 8% (9/108) were terminated. Only 78% (67/86) of live-born cases in which CHD had been diagnosed antenatally survived the neonatal period, compared to 93% (221/238) with a postnatal diagnosis of CHD (P < 0.001).

CONCLUSIONS

Even with a relatively simple training program, significant improvements can be made in the antenatal detection of CHD. With training, obstetric sonographers can successfully assess outflow tracts. Antenatally diagnosed cases have more complex CHD and this probably contributes to poor neonatal survival.