Background
Aortic arch reconstruction in neonates is commonly performed using deep hypothermic circulatory arrest. However, concerns have arisen regarding potential adverse neurologic outcomes from this complex procedure, raising questions as to best arterial cannulation approach for cerebral perfusion and effective systemic hypothermia. In this study, we use computational fluid dynamics to investigate the impact of different cannulation strategies in neonates.
Methods
Using a realistic hypoplastic neonatal aorta template as the base geometry, four different cannulation options were investigated: 1) right innominate artery, 2) innominate root, 3) patent ductus arteriosus (PDA), or 4) both innominate root and PDA. Performance was evaluated based on the numerically predicted cerebral and systemic flow distributions compared with physiological perfusion under neonatal conditions.
Results
The four cannulation strategies were associated with different local hemodynamics, but this did not translate into any significant effect on the measured flow distributions. The largest difference only represented 0.8% of the cardiac output and was measured in the innominate artery, which received 23.2% of the cardiac output in Option 3 vs. 24% in Option 4. PA snaring benefited all systemic vessels uniformly.
Conclusion
Due to the very high vascular resistances in neonates, flow distribution to the different vascular beds was dictated by the downstream vascular resistances rather than the cannulation strategy, allowing the surgical team to choose their method of preference. However, patients with aortic coarctation warrant further investigation and will most likely benefit from a two cannulae approach (Option 4).