Fluid dynamic characterization of a novel branching anastomosis design

Geometric characteristics of a vascular anastomosis can have important biomechanical impacts, particularly in the hemodynamic context of wall shear stress (WSS). In this study, we propose a new branching anastomosis design, the Hybrid anastomosis, to connect a donor vessel to two recipient vessels. The central obstruction characteristic of the traditional Figure 8 anastomosis is mitigated by creating a recessed lumen at the bifurcation. Chicken vessels were used to create and test three Figure 8 and three Hybrid anastomoses ex vivo. Computational fluid dynamics (CFD) simulations of idealized anastomosis designs were then used to verify the experiments and further studied the WSS and WSS gradient (WSSG) profiles of the designs. Experimental results showed increased flow through the Hybrid anastomosis (0.40 ml/s vs. 0.23 ml/s). The mean suture time averaged 20 and 28 min for the Figure 8 and Hybrid anastomoses, respectively. CFD simulations agreed with the experiments; the simulations showed lower flow resistance in the Hybrid anastomosis (1.89 kPa-s/ml vs. 6.77 kPa-s/ml). Most importantly, a set of more physiologically realistic simulations showed that the Hybrid anastomosis reduced WSS and WSSG by over 60% as compared to the Figure 8. Results demonstrated that the proposed Hybrid anastomosis can be created on a comparable surgical time scale (and from the same initial vasculature) as compared to the Figure 8 anastomosis, while decreasing flow resistance and reducing WSS and WSSG considerably. These findings support that the new Hybrid anastomosis may represent a favorable surgical alternative to the Figure 8 design.