Blood flow through sutured and coupled microvascular anastomoses: a comparative computational study

This study uses computational fluid dynamics (CFD) to model blood flow through idealised sutured and coupled arterial anastomoses to investigate the affect of each technique on intravascular blood flow. Local flow phenomena are examined in detail to study characteristics that potentially initiate thrombus formation; for example, changes in velocity profile, wall shear stress (WSS), and shear strain rate (SSR). Idealised geometries of sutured and coupled anastomoses were created with dimensions identical to microvascular suture material and a commercially available coupling device using CFD software. Vessels were modelled as non-compliant 1 mm diameter ducts, and blood was simulated as a Newtonian fluid, in keeping with previous studies. All analyses were steady-state and performed on arteries. The sutured simulation revealed a reduced boundary velocity profile; high WSS; and high SSR at the suture sites. The coupled anastomosis simulation showed a small increase in maximum WSS at the anastomotic region compared to a pristine vessel, however, this was less than half that of the sutured model. The coupled vessel displayed an average WSS equivalent to a pristine vessel simulation. Taken together these observations demonstrate a theoretically more thrombogenic profile in a sutured anastomosis when compared to a coupled vessel. Data from simulations on a coupled anastomosis reveal a profile that is nearly equivalent to that of a pristine vessel. Based purely on the combination of less favourable flow properties shown using these idealised arterial models, the sutured method is potentially more thrombogenic than a coupled anastomosis.