Multidisciplinary Management of Fetal Single Ventricle Cardiac Defects Boosts Outcomes

Research study background

Hypoplastic right heart syndrome (HRHS) and hypoplastic left heart syndrome (HLHS) are two rare and life-threatening types of single ventricle cardiac defects (SVCD). While medical advances have increased the prenatal detection rate and significantly improved SVCD outcomes, better understanding maternal and fetal comorbidities could offer insight into risk-reducing treatments.

In 2013, the Colorado Fetal Care Center at Children’s Hospital Colorado implemented a multidisciplinary protocol that includes fetal cardiologists and maternal fetal medicine specialists for obstetrical management and delivery of prenatally diagnosed HRHS and HLHS. This retrospective review describes the team’s experience co-managing cases from 2013 to 2022 and compares maternal-fetal comorbidities, and delivery and postnatal outcomes between HRHS and HLHS.

Multidisciplinary Management Protocol for Fetal Single Ventricle Cardiac Defects

Of the 181 fetal SVCD cases included in the study, 152 were livebirths planned for cardiac intervention. Ultimately, 147 infants survived to their first intervention (107 HLHS and 40 HRHS) and 137 infants were discharged to home. The percentage of infants surviving to hospital discharge was the same for HLHS and HRHS. Survival to at least one year was significantly higher in the HRHS group (97.6% compared to 82.9%) and the length of hospital stay for these infants was significantly lower (15 days compared to 43).

Term deliveries occurred for 86% of the liveborn infants planned for intervention, with no difference in delivery timing, indication and mode of delivery between conditions. There were more spontaneous preterm births than iatrogenic in both groups due to the premature rupture of membranes. There were 57 cesarean section deliveries, 36 of which were planned.

There were no significant differences in maternal and prenatal fetal comorbidities between HRHS and HLHS. This included fetal growth restriction (FGR), prematurity, maternal hypertension, maternal obesity, fetal extracardiac anomalies and chromosome anomalies. FGR occurred in 17% of the entire cohort, which is a much higher rate than the general obstetrical population. Most of the cases were severe early onset, but this didn’t impact short- and long-term neonatal survival.

A multivariate analysis of risk factors and co-morbidities found that only earlier gestational age at delivery and oligohydramnios (low amniotic fluid) predicted decreased odds of survival at one year. Although the two factors are co-dependent, each is a significant predictor of death before hospital discharge.

Clinical implications

This study demonstrates that consistent use of a multidisciplinary prenatal management protocol for SVCD leads to high first-year survival and low pregnancy interruption rates, which could be helpful for other fetal centers caring for these types of patients. Study authors recommend more in-depth family counseling about the predictors of postnatal death common in SVCD. Clinicians should also inform parents that early delivery or oligohydramnios may necessitate increased surveillance and other management changes. The team plans to evaluate their experience with other cardiac conditions in future studies.