Fetal Echocardiographic Variables Associated with Pre-Surgical Mortality in Truncus Arteriosus: A Pilot Study

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 pre-surgical mortality in prenatally detected TA. This two-center, retrospective cohort study included fetuses diagnosed with TA between 01/2010 and 04/2020. The primary outcome was pre-surgical mortality, defined by fetal or neonatal pre-surgical death or primary listing for transplantation prior to discharge. Univariable regression modeling, Chi-square tests, and t tests assessed for associations between prenatal clinical, demographic, and fetal echocardiographic (fetal-echo) variables and pre-surgical mortality. Of 23 pregnancies with prenatal diagnosis of TA, 4 (17%) were terminated. Of the remaining 19, pre-surgical 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 pre-surgical 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 < 7 (0% vs. 40%; p = 0.01), skin edema (0% vs. 40%; p = 0.01), and abnormal umbilical venous (UV) Doppler (0% vs. 60%; p = 0.002). The presence of truncal valve regurgitation or stenosis neared significance. In this cohort with prenatally diagnosed TA, there is significant pre-surgical mortality, including fetal death and neonatal pre-surgical death. Termination rate is also high. Fetal-echo variables associated with pre-surgical mortality in this cohort include ventricular dysfunction, low CVP, skin edema, and abnormal UV Doppler. Knowledge about prenatal risk factors for pre-surgical mortality may guide parental counseling and postnatal planning in prenatally diagnosed TA.