Foetal echocardiogram precisely detects congenital heart diseases

Use of foetal echocardiograms results in an accurate diagnosis of congenital heart diseases (CHDs), with good concordance between pre- and postnatal diagnoses, according to a Singapore study.

“As CHD is the most common foetal anomaly and with 22.7 percent being associated with genetic abnormalities, foetal CHD diagnosis may increasingly serve as a gateway for antenatal genetic diagnoses,” the researchers said. “High-quality genetic counselling and testing is essential.” [Circulation 2011;123:841-849]

This single-centre cohort study assessed all major foetal CHDs that had been detected on routine obstetric foetal anatomical ultrasound scans between January 2014 and December 2017 in an unselected population. The researchers then stratified the demographic details, foetal echocardiogram reports, genetic test results, delivery outcomes, and postnatal progress by CHD subtype.

A total of 20,031 screened pregnancies were included, of which 109 (0.53 percent) were diagnosed with a major foetal CHD. Coarctation of aorta (17.4 percent) was the most common CHD subtype, followed by transposition of great arteries (16.5 percent), and tetralogy of Fallot and univentricular hearts (13.8 percent each). [Ann Acad Med Singap 2023;52:420-431]

Many of the pregnancies with foetal CHD diagnoses (60.5 percent) underwent confirmatory genetic testing (eg, karyotyping and testing for 22q11 microdeletion). Of these, nearly a quarter had abnormalities, of which 22q microdeletion was the most common.

Complete obstetric data was available in 85 pregnancies (78 percent), of which 76.5 percent progressed to live birth. Most of these births (92.1 percent) underwent postnatal echocardiograms, which were consistent with the antenatal ones.

At age 4 years, 43.2 percent of the offsprings showed no medical or developmental issues, 20.0 percent had mild medical or developmental issues, 21.5 percent had major medical or developmental issues, and 12.3 percent died.

“A repeat study with a similar format involving present-day practices, which include chromosomal microarray and next generation sequencing, would help develop local guidelines for counselling CHD,” the researchers said.

Antenatal diagnosis

Previous studies did not demonstrate a significant mortality benefit associated with antenatal CHD diagnosis, but recent meta-analyses revealed a marked decrease in invasive respiratory support, fewer perioperative neurologic events, and earlier initiation of prostaglandin E1 therapy. [Am J Cardiol 2011;108:421-427; Prenat 2012;32:1250-1255; Ultrasound Obstet Gynecol 2015;45:631-638; Pediatr 2010;31:587-597; Pediatrics 2001;107:1277-1282; Am J Cardiol 2011;108:421-427]

The latter findings were likely brought about by better antenatal counselling, coordination of delivery resources, and facilitation of postnatal care and procedural planning. [Am J Cardiol 2011;108:421-478; Am J Cardiol 2011;108:421-427]

“Furthermore, accurate antenatal diagnosis will play an important role in facilitating nascent foetal cardiac interventions, such as aortic valvuloplasties, to prevent progression of aortic stenosis into hypoplastic left heart syndrome,” the researchers said. [Ultrasound Obstet Gynecol 2018;52:212-220]

Asia holds the record for the highest birth prevalence of CHDs (9.3 per 1,000 live births), but significant inter-regional disparities exist potentially due to differences in factors such as nutrition, consanguinity, maternal age, ethnicity, abortion patterns, temporal changes in CHD prevalence, availability of accurate foetal diagnosis, and reporting standards. [J Am Coll Cardiol 2011;58:2241-2247; J Pedriatr 2013;162:108-13.e2; JAMA Cardiol 2018;3:829-837; Singapore Med J 2005;46:545-552; Ann Hum Biol 2006;33:519-528; J Ultrasound Med 2011;30:989-995; Pediatr Cardiol 2006;27:465-472]

“Our cited prevalence is similar to that cited in a recent extensive systematic review involving European populations (6.51 per 1,000 foetuses), although a higher proportion were conotruncal abnormalities (44.0 percent vs 20 percent),” the researchers said.

“This may also be due to a selection bias arising from our centre’s status as a major referral centre for complicated foetal anomalies,” they added.