Cannulation strategy for aortic arch reconstruction using deep hypothermic circulatory arrest

Abstract

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 about the best arterial cannulation approach for cerebral perfusion and effective systemic hypothermia. In this study, we use computational fluid dynamics to investigate the effect of different cannulation strategies in neonates.

Methods: We used a realistic template of a hypoplastic neonatal aorta as the base geometry to investigate four cannulation options: (1) right innominate artery, (2) innominate root, (3) patent ductus arteriosus (PDA), or (4) innominate root and PDA. Performance was evaluated according to the numerically predicted cerebral and systemic flow distributions compared with physiologic perfusion under neonatal conditions.

Results: The four cannulation strategies were associated with different local hemodynamics; however, 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. Pulmonary artery snaring benefited all systemic vessels uniformly.

Conclusions: Because of the very high vascular resistances in neonates, downstream vascular resistances dictated flow distribution to the different vascular beds 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 2-cannulae approach (option 4).

Figure 1

A: Geometry of the idealized hypoplastic aorta. B: The four cannula insertion locations. The cannula is shown in red, while the hypoplastic aorta is shown in gray.

Figure 2

Schematic representation of the inflow and outflow boundary conditions.

Figure 3

Comparison of the flow distributions and velocity fields associated with the four cannulation options with PA snaring. S1, S2, S3: flow splitting points. A: Option 1; B: Option 2; C: Option 3; D: Option 4.

Figure 4

Comparison of the flow distributions and velocity fields associated with the four cannulation options, under “adult” flow conditions. A: Option 1; B: Option 2; C: Option 3; D: Option 4.