Prenatal detection rate of major congenital heart defects in Copenhagen from 2015 to 2018

Abstract

Prenatal detection of congenital heart defects (CHD) may improve perinatal outcome and, in some types of CHD, may reduce mortality1. It may also prompt genetic testing, allowing parents to prepare for the arrival of a sick child or, when severe, to have the choice to terminate the pregnancy. We aimed to evaluate the prenatal detection of major CHD in greater Copenhagen, Denmark. The data for this retrospective, register-based study were derived from a low-risk population attending three university hospitals in Copenhagen, Denmark and included all fetuses, terminated or liveborn, and children with a prenatal or postnatal diagnosis of major CHD between 1 January 2015 and 31 December 2018. All pregnancies had a first- and/or second-trimester ultrasound examination. Data were retrieved from the National Danish Fetal Medicine Database (FØTOdatabasen)2. All diagnoses were validated in our clinical systems, Astraia and The Healthcare Platform from Epic. We crosschecked the retrieved data from the database and searched for additional cases in the local Astraia systems and the electronic patient files. The findings on prenatal echocardiography were compared to those on neonatal echocardiography to evaluate the accuracy of the prenatal diagnosis. In terminated pregnancies, the autopsy report was reviewed, if available. The study was approved by The Danish Data Protection Agency (P-2019-152) and the Danish Patient Safety Authority (3-3013-3050/1). All women in Denmark are offered first- and second-trimester screening examinations free of charge. All examinations are performed by midwives and nurses trained to perform the scans in accordance with the Fetal Medicine Foundation standards, and they report the results without review by doctors, who are involved only in cases with suspected anomaly. A fetus with suspected CHD is first examined by a fetal medicine specialist who then refers the case with a likely CHD to the fetal/pediatric cardiology team. The national guideline for screening for CHD includes examination in the end-diastolic four-chamber view, left-ventricular-outflow-tract view including the aortic valve, three-vessel view including the pulmonary valve and the three-vessels-and-trachea view. We included cases with major CHD defined according to Lytzen et al. as complex malformation of the heart and great arteries usually requiring intervention within 1 year after birth3. The diagnoses are listed in Table 1 in order of severity, along with the overall detection rates. Those with multiple diagnoses were allocated to the most severe lesion. All but one of the surviving children underwent surgery within 1 year after birth. CHD cases extracted from the database are shown in Figure 1. In the same period, a total of 71 697 children were born in the greater area of Copenhagen4, resulting in a prevalence of major CHD of 0.2%. Of the 143 cases with major CHD, 127 were identified prenatally (89%; 95% CI, 82–93%) (Table 1), of which 98 were confirmed by autopsy or neonatal echocardiography (29 fetuses terminated without an autopsy performed). Among the 98 cases with a confirmed diagnosis, we found only one case with an inconsistency between prenatal and postnatal major diagnostic categories, in which the prenatal diagnosis was transposition of the great arteries and the postnatal diagnosis was congenitally corrected transposition of the great arteries, resulting in a prenatal diagnostic precision of 99%. Baseline characteristics are listed in Table S1. We found a higher body mass index in mothers of children with a prenatally undetected CHD (P < 0.01). Validation of the diagnoses from the National Danish Fetal Medicine Database was performed, and the results are shown in Table S2. We found no inconsistencies between the postnatal diagnoses in the database and clinical diagnoses in the patient files. The prenatal detection rate of CHD has previously been low when compared with that of other malformations5. However, the present findings from three centers, alongside those of a recent study6, suggest that the prenatal detection rate of major CHD is higher than previously reported. A new, national study in Denmark is desirable to assess whether the improvements are observed across the whole country. Moreover, future studies on detection rate of major CHD should aim to also include cases with total anomalous pulmonary venous return. Table S2 Prenatal validation of registered data from the Danish Fetal Medicine Database Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

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