Complex Screening for Congenital Cardiovascular Malformations

Importance: Congenital heart defects constitute the most prevalent developmental abnormality. Among these, critical congenital heart defects are associated with substantial morbidity and mortality if not promptly identified. Objective: To evaluate the screening performance of a newborn protocol combining prenatal ultrasonography, postnatal physical examination, and pulse oximetry screening, with particular attention being paid to the timing of the postnatal examination. This is an evaluation of screening performance in a single centre and not a study of birth prevalence. Methods: We performed a retrospective cohort study of all live-born infants delivered at University of Szeged, Hungary, between 2019 and 2024. Screening comprised prenatal ultrasonography, postnatal physical examination within 24 h and at a 48–72 h range, and pulse oximetry screening at 24 ± 6 h. The primary outcome was an echocardiographically confirmed congenital heart defect, classified as critical, severe, requiring surgical correction after one year of age, or minimal. Isolated patent foramen ovale, isolated patent ductus arteriosus when the only echocardiogram was performed before 21 days of age, and a patent duct in preterm infants were classified as transitional findings and were excluded. Proportions are reported with exact (Clopper–Pearson) 95% confidence intervals and groups were compared using Fisher’s exact test. Results: Among 13,979 live births, 123 infants had an echocardiographically confirmed structural defect of the heart or great vessels detected through screening; a further 39 infants had transitional findings. Postnatal physical examination accounted for 107/123 (87.0%, 95% confidence interval range: 79.7–92.4) of the cases detected by screening; because echocardiography was not performed in screen-negative infants and defects presenting after discharge were not systematically traced, this is the share of screen-detected cases and not the sensitivity of the examination. The second examination at the 48–72 h range accounted for 92/123 (74.8%, 66.2–82.2), including 3 critical and 5 severe defects in which the first examination had shown no abnormality. Prenatal ultrasonography identified 6/16 (37.5%, 15.2–64.6) of critical and severe defects, and 15/123 (12.2%, 7.0–19.3) of all structural defects. The latter figure is not a prenatal detection rate, since there are lesions that cannot be identified before birth. Pulse oximetry screening identified 1/123 (0.8%, 0.0–4.4) after negative prenatal ultrasonography and no clinical signs. The combined protocol detected 123 of the 124 infants known to have a structural defect (99.2%) before discharge; this is a detection rate among known cases. Critical defects were identified in at least 0.50 per 1000 live births and critical plus severe defects in at least 1.14 per 1000; these are lower limits for live births in one centre, not birth prevalence estimates. Interpretations: Repeated postnatal physical examination provided the highest yield, while prenatal ultrasonography contributed mainly to severe and critical defect detection; pulse oximetry screening added few additional cases but remains an important modality. Where discharge occurs before 48 h, a second cardiac examination should be arranged at a range of 48–72 h of age, and a cardiology review between two and six weeks is advisable, since small muscular ventricular septal defects and duct-dependent left-heart obstruction may not be apparent in the first days of life.