Prenatal Imaging and Outcome of Fetal Heterotaxy: A Retrospective, Single-Center Evaluation over 21 Years

Objectives: Heterotaxy is defined as an abnormal arrangement of inner organs across the left-to-right axis of the heart. Left-atrial isomerism (LAI) is frequently associated with fetal arrhythmia and two-ventricle congenital heart disease (CHD), whereas right-atrial isomerism (RAI) is typically associated with more complex CHD. Both LAI and RAI can exhibit various noncardiac anomalies with serious impact on fetal outcome. The aim of our study was to evaluate prenatal structural and functional abnormalities using ultrasound (US) and fetal magnetic resonance imaging (MRI), as well as long-term outcomes of fetuses with prenatal diagnosis of heterotaxy.

Methods: Retrospective analysis of ante- and postnatal imagings, morbidity, and mortality after prenatal diagnosis of heterotaxy from 1998 to 2019 in a tertiary referral center. For terminations of pregnancy, stillbirths, neonatal, and late deaths, autopsy reports were reviewed. Long-term outcome and surgical interventions were assessed for surviving infants. Fetal MRI was performed to assess additional nonabnormalities.

Result: Forty-six fetuses with heterotaxy and cardiovascular pathology, of which 28 (61%) had LAI and 18 (39%) RAI, were included. Parents chose termination of pregnancy in seven (7/28, 25%) fetuses with LAI and in seven (7/18, 39%) with RAI. Fetal arrhythmia was only present in the LAI group: 7 of 28 (25%) fetuses with LAI had higher degree AV-block of which four (4/28, 14%) developed intrauterine hydrops. Fetal MRI was abnormal in all 27 fetuses who underwent MRI. A new MRI finding was the presence of an additional medial liver lobe in 15 of 27 (55%) fetuses. Three fetuses revealed signs of total anomalous pulmonary venous obstruction on fetal MRI. Prenatal US revealed noncardiac malformations (apart from situs and splenic anomalies) in 25 fetuses (25/46, 54%). Twenty-nine children (29/46, 63%) were liveborn (17 LAI, 12 RAI). Nine (9/29 31%) had a biventricular anatomy. Of the 18 fetuses with a univentricular malformation, three were primarily palliated but converted to biventricular thereafter. Five children with RAI reached the Fontan procedure after palliative surgery (5/12, 42%). Overall, 15 of 29 (51%) children were alive at the time of data collection at a median age of 6 years (6 months–18 years).

Conclusion: Fetal MRI detects additional cardiac and noncardiac anomalies that may play a role in heart surgery after birth and allows more precise prenatal counseling. Survival in our cohort was comparable to data in literature and is inferior to nonheterotaxy patients with CHD

Publication History

Article published online:
21 February 2021