Abstract 11120: Congenitally Corrected Transposition of the Great Arteries - Fetal Diagnosis, Associations and Natural History: A Fetal Heart Society Research Collaborative Study

Abstract

Introduction: Congenitally corrected transposition of the great arteries (ccTGA) is rare with varied associated cardiac defects and rhythm abnormalities. We aimed to describe the natural history, associated anomalies and prenatal outcome in a cohort of prenatally diagnosed patients in which biventricular repair is anticipated. Methods: A retrospective cohort study was conducted via the Fetal Heart Society Research Collaborative. All fetuses with ccTGA encountered at 15 North American cardiac centers between 1/2004-7/2020 were identified. Fetuses with a hypoplastic ventricle precluding biventricular repair were excluded. Data is presented as median (interquartile range). Results: Inclusion criteria were met in 139 fetuses who were diagnosed with ccTGA at 24 (21-29) weeks. There was a family history of congenital heart disease in 12%. Maternal diabetes was present in 10%. Prenatal genetic testing in 50 pregnancies was normal. Excluding 14 fetuses with heterotaxy, extracardiac anomalies were observed in 9/125 (7.1%). Associated cardiac/extracardiac defects are detailed in table 1. Fetal atrioventricular block (AVB) was present in 17 fetuses (12%), diagnosed at a median of 26 (23-28), range 20-36 weeks. Two fetuses had SVT; 1 self-resolved and 1 during labor. Change occurred during follow-up in 34 fetuses, most commonly in severity of tricuspid regurgitation (6 improved, 4 worsened) and worsening of pulmonary stenosis (n=5). There were 112 live births, 17 terminations, 2 fetal deaths (FD) and 8 lost to follow-up. Both fetuses with FD had AVB, making the intrauterine mortality associated with fetal AVB 11.8% (2/17). Conclusions: This study represents the largest cohort to date of fetuses with ccTGA. Fetal ccTGA is associated with a spectrum of cardiac defects that may evolve, with extracardiac pathology occurring in 7.1%. AVB is found in 12% of fetuses and is a risk factor for FD. This data informs fetal counseling and can aid in delivery planning and perinatal care.