Fetal Echocardiographic Variables Associated with Perinatal Mortality in Truncus Arteriosus – A Pilot Study

Background: Truncus arteriosus (TA) is a rare congenital heart defect that can be prenatally detected by fetal echocardiography. However, prognostication and prenatal counseling focus primarily on surgical outcomes due to limited fetal and neonatal pre-surgical mortality data. We aimed to describe the incidence and identify predictors of perinatal pre-surgical mortality in prenatally detected TA. Methods: : This two-center, retrospective cohort study included fetuses diagnosed with TA between 01/2010 and 04/2020. The primary outcome was perinatal mortality, defined by fetal or neonatal pre-surgical death or transplantation prior to discharge. Univariable regression modeling and Chi-square test assessed for associations between prenatal clinical, demographic, and fetal-echo variables and perinatal mortality. Results: : Of 23 pregnancies with prenatal diagnosis of TA, 4(17%) were terminated. Of the remaining 19, perinatal mortality occurred in 4(26%), including 2(11%) fetal deaths and 2(11%) neonatal pre-surgical deaths. No transplantation listings. Of liveborn fetuses(n=17), 15(88%) underwent a neonatal surgery, and 1(6%) required ECMO. As compared to the survivors, the perinatal mortality group had a higher likelihood of having left ventricular dysfunction (0%vs.40%;p=0.01), right ventricular dysfunction (0%vs.60%;p=0.002), cardiovascular profile score(CVP)<7(0%vs.40%;p=0.01), skin edema (0%vs.40%;p=0.01), and abnormal umbilical venous(UV) Doppler (60%vs.0%;p=0.002). Presence of truncal valve regurgitation or stenosis neared significance. Conclusion: In prenatally diagnosed TA, there is significant perinatal mortality, including fetal death and neonatal pre-surgical death. Termination rate is also high. Fetal echocardiographic variables associated with perinatal mortality include ventricular dysfunction, low CVP, skin edema, and abnormal UV Doppler. Knowledge about prenatal risk factors for perinatal mortality may guide parental counseling and guide postnatal planning in prenatally diagnosed TA.