Screening model examines neonatal detection of congenital heart defects
1. In a mathematical model, an equal number of cases of congenital heart disease (CCHDs) were detected and missed by universal pulse-oximetry screening.
2. The model predicted that prevalence of prenatal detection did not have a significant impact on the overall number of diagnosed cases.
Study Rundown: The use of pulse-oximetry screening for CCHDs has become more common, although not universal, in the United States. While the method varies, many institutions follow the American Academy of Pediatrics guidelines, which recommend screening infants between 24 and 48 hours of life with pre- and post-ductal oxygen saturations. This study attempted to predict the efficacy of universal pulse-oximetry CCHD screening in the US. A mathematical model was implemented, which combined national and regional data to simulate universal newborn CCHD screening in the US. The model predicted that screening would detect approximately 900 non-syndromic infants with CCHD annually and that a similar number would not be detected. When comparing scenarios of high prenatal diagnosis and low prenatal diagnosis, there was minimal difference in the overall detection of CCHD by the third day of life. Limitations include use of data from 2000 to 2005, with significant growth in the field since then. In addition, the use of regional data as a basis for extrapolation may not reflect the entire United States. Nonetheless, this analysis suggests that screening not be used as the sole basis for diagnosis of CCHD and that further prospective study of both prenatal and newborn screening would be beneficial.
Click to read the study, published today in Pediatrics
Relevant Reading: Late Detection of Critical Congenital Heart Disease Among US Infants
In-Depth: This study created a mathematical simulation of CCHD rates. Live-birth data and prenatal diagnosis rates were taken from a metropolitan Atlanta active surveillance project and 10 US sites, respectively, between 2000 and 2005. Cases with concurrent syndromic or chromosomal abnormalities were excluded. Using this data along with pooled estimates of pulse oximetry sensitivity for CCHDs, a Monte Carlo simulation was performed resulting in 10,000 samples. The high variability of prenatal diagnosis prompted a secondary analysis comparing a higher and lower prenatal detection rate.
The simulation estimated the presence of 5,965 (95% UI: 5415-6515) infants born with at least 1 non-syndromic CCHD each year in the U.S. An estimated 2410 (95% UI*: 2150-2680) would receive a diagnosis within 3 days of life (without the assistance of CCHD screening) while 1755 (95% UI: 1540-1980) were diagnosed after 3 days of life (the group most likely to benefit from screening). Assuming universal screening and average rates of prenatal diagnosis (30%), 875 (95% UI: 705-1060) infants were detected annually by pulse-oximetry while 880 (95% UI: 700-1080) were false-negatives. The false-negatives were mainly coarctation of the aorta, interrupted aortic arch, and tetralogy of Fallot. Assuming “low” (21%) rates of prenatal diagnosis, an estimated 1105 (95% UI: 885-1350) true-positives and 1020 (95% UI: 805-1260) false-negative CCHD cases resulted from newborn screening. Assuming “high” (41%) rates of prenatal diagnosis, 740 (95% UI: 575-925) true-positives and 785 (95% UI: 610-975) false-negatives were found using newborn screening.
*Uncertainty interval (UI) is defined by the 2.5th and 97.5th percentiles of the distribution of simulated values from the Monte Carlo model.
Image: PD
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