Influence of prenatal diagnosis on congenital heart defects

Does the Use of Diagnostic Technology Reduce Fetal Mortality?

OBJECTIVE

To examine the effect that the introduction of new diagnostic technology in obstetric care has had on fetal death.

DATA SOURCE

The Medical Birth Registry of Norway provided detailed medical information for approximately 1.2 million deliveries from 1967 to 1995. Information about diagnostic technology was collected directly from the maternity units, using a questionnaire.

STUDY DESIGN

The data were analyzed using a hospital fixed-effects regression with fetal mortality as the outcome measure. The key independent variables were the introduction of ultrasound and electronic fetal monitoring at each maternity ward. Hospital-specific trends and risk factors of the mother were included as control variables. The richness of the data allowed us to perform several robustness tests.

PRINCIPAL FINDING

The introduction of ultrasound caused a significant drop in fetal mortality rate, while the introduction of electronic fetal monitoring had no effect on the rate. In the population as a whole, ultrasound contributed to a reduction in fetal deaths of nearly 20 percent. For post-term deliveries, the reduction was well over 50 percent.

CONCLUSION

The introduction of ultrasound made a major contribution to the decline in fetal mortality at the end of the last century.

Reducing the cost of detection of congenital heart disease in fetuses of women with pregestational diabetes mellitus

OBJECTIVE

To provide a cost minimization analysis to support a paradigm shift in the use of comprehensive ultrasound and echocardiography in the prenatal diagnosis of congenital heart disease (CHD) in fetuses of women with diabetes mellitus (DM).

METHODS

In this retrospective cohort study, the diabetic clinic service database of the University of California San Diego was searched from January 2001 to June 2004 for pregnant women with Type I or II DM and HbA1c >6.3%. Subjects underwent comprehensive ultrasound examination (with four-chamber views and outflow tracts) and fetal echocardiography according to a standard protocol. Newborns were examined for cardiac defects and underwent postnatal echocardiography as indicated. The cost of screening was evaluated.

RESULTS

Of 115 neonates and two terminations of pregnancy there were 20 (17%) cases of CHD. Six of these CHD were major and all six were detected prenatally by both ultrasound and echocardiography. Three additional clinically insignificant cases of CHD were identified by fetal echocardiography. Eleven cases of CHD were identified by postnatal echocardiography only, all of which were clinically insignificant lesions. The prenatal detection rate of major CHD was 100% (6/6) for both ultrasound and echocardiography. The sensitivites of ultrasound (30% (95% CI, 13-54%)) and echocardiography (45% (95% CI, 24-68%)) were similar (P = 0.32). A cost minimization analysis was done using the published Medicaid (California) system's relative value unit and conversion factors. Accordingly, our current protocol costs $6503.43 per case of major CHD detected. If echocardiography had been performed only as indicated and postnatal echocardiography had been performed on all neonates, the cost would have been $7056.83 per case of major CHD detected. Alternatively, combined targeted ultrasound with indicated prenatal and postnatal echocardiography would have been associated with a cost of $4996.05 per case of major CHD detected.

CONCLUSION

Detection of major CHD was excellent with both comprehensive prenatal ultrasound and echocardiography. Echocardiography added little to the prenatal diagnosis of CHD if the comprehensive ultrasound examination was normal. The highest cost-benefit ratio and most efficacious protocol for screening based on our data would be comprehensive ultrasound with prenatal and postnatal echocardiography only as indicated. Further prospective studies are warranted.

Is the nuchal index increased in fetuses with congenital structural heart defects?

OBJECTIVES

To determine if the Nuchal index (NIx) is increased in euploid fetuses with structural congenital heart defects (CHD).

METHODS

Euploid fetuses with CHD between 18 and 24 weeks gestation were identified. The next fetus meeting the same criteria with a normal fetal echocardiogram were selected as a control. The NIx [(mean nuchal thickness /mean biparietal diameter) x 100] and cardiac axis (CA; degrees) were calculated for each fetus. Standard descriptive tests and two-tailed t test were used.

RESULTS

The NIx in the abnormal (n = 20) and control (n = 20) groups were 9.10 (2.35) and 7.54 (p = 0.04) and CA was 55.8 degrees and 48.6 degrees (p = 0.02), respectively.

CONCLUSIONS

The NIx and CA were significantly different in fetuses with CHD. A prospective study to confirm these findings and determine clinical utility is warranted.

Transhepatic Ultrasound-Guided Cardiac Catheterization in the Fetal Lamb

BACKGROUND

Percutaneous transventricular and fetoscopic umbilical catheterization have been applied to animal and human fetuses. These methods have a high rate of failure and complications. Here, we propose an alternative route for anterograde echocardiography-guided cardiac catheterization through a transhepatic approach of the intra-abdominal vessels in the fetal lamb.

METHODS AND RESULTS

After exteriorization of the uterus in 12 pregnant ewes between 118 to 122 days' gestation, a 4F sheath mounted over a 1.2-mm needle was placed into the intra-abdominal portion of the umbilical vein (n=2) and into the subdiaphragmatic portion of the inferior vena cava via a transhepatic approach (n=10) under ultrasound guidance. In the first 2 animals using a transumbilical approach, it was impossible to reach the heart through the ductus venosus. In the next 10 animals, using a conventional technique, echocardiography-guided catheterization of the 4 chambers was performed in the all fetuses, atrial or ventricular pacing in 6 fetuses, and ballooning of the pulmonary valve in 9 of 10 fetuses. Among the 10 fetuses catheterized through the transhepatic approach, 2 were euthanized immediately after the procedure to evaluate intraperitoneal bleeding (23 and 29 mL, respectively), and 3 died after the procedure (1 of major bleeding and 2 deaths related to balloon catheter manipulation). Finally, 5 were delivered vaginally after an uneventful pregnancy, and autopsy at day 5 did not show significant liver, vascular, or cardiac injury.

CONCLUSIONS

Echocardiography-guided fetal cardiac catheterization through a transhepatic approach is feasible and provides an interesting alternative approach for human fetal cardiac interventions.

What's Happening in Paediatric Cardiology?

Recent decades have witnessed dramatic advances in the care of adults with heart disease. However, equally significant advances have occurred in the care of children. In this review we describe some of the advances, which have been made in the care of children with heart disease, focusing not only on technological advances, but also on developments in team-based care, which together have resulted in significant improvements in outcomes.

Trends in prenatal diagnosis of critical cardiac defects in an integrated obstetric and pediatric cardiac imaging center

OBJECTIVE

Prenatal diagnosis of critical (requiring neonatal intervention) cardiac defects (critical congenital heart diseases (CCHD)) improves survival, yet detection of such malformations is poor. Our institution changed its practice and integrated a pediatric cardiologist into the perinatal team. The purpose of this study was to evaluate how this change affected the rate of detected congenital heart disease (CHD) and the diagnostic accuracy.

STUDY DESIGN

Obstetrical ultrasounds of mothers at high and normal risk for fetal CCHD at a single center between 1991 and 2001 were reviewed. Rate of detected CCHD, positive predictive values and false positives were compared before and after pediatric cardiology integration.

RESULTS

Between the first and second time periods, the rate of detected CCHD increased from 6.8/1000 ultrasounds to 12.9/1000 ultrasounds (p=0.007), and positive predictive value increased from 75 to 96%.

CONCLUSION

Collaboration with pediatric cardiology can significantly improve the rate of detected CCHD. These findings have significant implications for sonographer education and patient care.

Parents' Perspectives on Decision Making After Antenatal Diagnosis of Congenital Heart Disease

OBJECTIVE

To discover and describe how prospective parents make decisions when they learn of their baby's congenital heart disease (CHD) during pregnancy, and to provide professionals with direction for their interactions with these families.

DESIGN AND METHOD

Qualitative analysis informed by symbolic interactionism.

SETTING

A tertiary care women's health center that provided referral services for a province with a population of 4 million.

PARTICIPANTS

Mothers and fathers of 19 babies with antenatally diagnosed CHD participated in interviews during pregnancy and after the birth of their baby. Thirty-four interviews were analyzed for common themes and distinguishing characteristics of antenatal decision making.

RESULTS

Parents approached their antenatal decisions regarding further testing and continuation of the pregnancy as their first parenting decisions. They made their decisions with differing degrees of apparent ease or deliberation, and some parents more readily sought the opinion of professionals. The offered opinions offended some parents, even though the professionals may have intended the information as descriptive of options, not suggestive of a particular decision.

CONCLUSION

Although advances in technology have enabled diagnosis of CHD antenatally, health care professionals, including nurses, must elicit each parent's particular perspective, be cognizant of their professional influence, and actively support parents from the time of the antenatal diagnosis.

Genetic counseling throughout the life cycle

As the definition of genetic counseling continues to evolve, so does the application of genetic counseling services in all areas of medicine and throughout the human life cycle. While governmental policy, economics, ethics, and religion continue to influence society's views regarding the necessity of testing germ cells for mutations to prevent the birth of an affected child or predicting whether healthy adults will develop future life-threatening illness, patient autonomy in the choice of whether to know, or not know, one's genetic make-up remains a core principle of genetic counseling.

Antenatal ultrasound screening for fetal abnormalities: a systematic review of studies of cost and cost effectiveness

OBJECTIVE

To review systematically and critically evidence to derive estimates of costs and cost effectiveness of routine ultrasound screening for fetal abnormalities.

DESIGN

A systematic review of the literature using explicit criteria for inclusion of primary research studies, a stated electronic strategy to identify relevant material, and an explanation of why apparently relevant studies have not been included.

SETTING

All countries of origin were included. The results of this review are important to obstetricians and to health service managers in the allocation of resources, and others who are considering conducting further research in this area.

MAIN OUTCOME MEASURE

Formal economic evaluations and cost studies of routine ultrasound screening. Costs of routine anomaly scans and costs of other procedures carried out as part of antenatal screening by ultrasound.

RESULTS

One hundred and ninety-nine studies were identified in total, 24 reaching the final stage of the review. Nine studies were formal economic evaluations and 15 reported costs studies or clinical effectiveness studies with some assessment of cost. The studies were carried out mainly in Europe and in the United States. After quality criteria were applied, data were extracted from six of the economic evaluations and six of the costs studies. One economic evaluation conducted alongside a randomised trial concluded that screening for fetal abnormalities by ultrasound in the second trimester was cost effective, compared with routine antenatal care. The costs of routine scans ranged from Pound Sterling 18 to Pound Sterling 204 and for non-routine ranged from Pound Sterling 32 to Pound Sterling 113.

CONCLUSIONS

There is a lack of good quality primary studies of the costs of ultrasound screening in pregnancy. Typically, economic evaluations of ultrasound screening have been based on poor quality evidence of clinical effectiveness. There is a need for more published data on the costs and cost effectiveness of routine ultrasound screening for fetal anomalies, and of the longer term consequences of screening for anomalies.