Study of Multiple Systemic-to-Pulmonary Shunts in Single Ventricle Hearts

For newborns diagnosed with single ventricle hearts and insufficient blood flow to the lungs, their lack of oxygen in the blood can be remedied with a modified Blalock-Taussig shunt (BTshunt) between the innominate and pulmonary artery. However, some surgeons prefer to have two systemic-to-pulmonary shunts, by either leaving the ductus arteriosus open or construct a second BT shunt, to provide additional pulmonary blood flow. There have been clinical reports of premature shunt occlusion when more than one shunt is employed, and a recent audit of shunt operations at a single institution has revealed increased mortality. There are speculation that these adverse outcomes can be due to flow competition between the two shunts, and/or having too much pulmonary blood flow. The flow dynamics and cardiopulmonary physiology in single ventricle circulations where pulmonary blood flow is supplied by more than one shunt has not been studied previously. In this study, we adopted CFD-based multi-domain simulations to compare a range of shunt configurations to examine the issue of flow competition and pulmonary overcirulation.