Factors Associated With Interstage Mortality Following Neonatal Single Ventricle Palliation

Background: Several advances have led to improved hospital survival following neonatal palliation (NP) of single ventricle (SV) anomalies. Nonetheless, a number of patients continue to suffer from interstage mortality (ISM) prior to subsequent Glenn. We aim to study patients' characteristics and anatomic, surgical, and clinical details associated with ISM. Methods: A total of 453 SV neonates survived to hospital discharge following NP. Competing risk analysis modeled events after NP (Glenn, transplantation, or death) and examined variables associated with ISM. Results: Competing risk analysis showed that one year following NP, 10% of patients had died, 87% had progressed to Glenn, 1% had received heart transplantation, and 2% were alive without subsequent surgery. On multivariable analysis, factors associated with ISM were as follows: weight <= 2.5 kg (hazard ratio, HR = 2.4 [1.2-4.6], P = .013), premature birth <= 36 weeks (HR = 2.0 [1.0-4.0], P = .05), genetic syndromes (HR = 3.2 [1.7-6.1], P < .001), unplanned cardiac reoperation (HR = 2.1 [1.0-4.4], P = .05), and prolonged intensive care unit (ICU) stay >30 days following NP (HR = 2.5 [1.4-4.5], P < .001). Palliative surgery type (shunt, Norwood, band) was not associated with ISM, although aortopulmonary shunt circulation after Norwood was (HR = 5.4 [1.5- 1.9.2] P = .01). Of interest, underlying SV anatomy was not associated with ISM (HR = 1.1 [0.6-2.2], P = .749). Conclusions: In our series, ISM following NP occurred in 10% of hospital survivors. As opposed to hospital death, underlying SV anomaly was not associated with ISM. Conversely, several patient factors (prematurity, low weight, and genetic syndromes) and clinical factors (unplanned reoperation and prolonged ICU stay following NP) were associated with ISM. Vigilant outpatient management that is individualized to specific clinical and social needs, taking into account all associated factors, is warranted to improve survival in high-risk patients.