Blood Flow Simulation to Determine the Risk of Thrombosis in the Fontan Circulation: Comparison between Atriopulmonary and Total Cavopulmonary Connections

Abstract

Three-dimensional computational fluid dynamics (CFD) simulations were performed in the anastomotic region of the Fontan route between the venae cava and pulmonary arteries to investigate the risk of thrombosis due to blood stasis in the Fontan circulation. The finite volume method based on the time-averaged continuity and Navier–Stokes equations combined with the k-ω SST turbulent model was used in the CFD simulations. Low shear rate (SR) and SR on the wall (WSR) of <10 s−1 were used as markers to assess blood stasis as a cause of blood coagulation. Simulated blood flow velocity and both SR and WSR were reduced in the right atrium (RA) as the cavity of a flow channel in the atriopulmonary connection (APC) Fontan model, whereas the values increased in the total cavopulmonary connection (TCPC) Fontan model, which has no cavity. The volume of SR <10 s−1 and wall surface area of WSR <10 s−1 were, respectively, 4.6–261.8 cm3 and 1.2–38.3 cm2 in the APC Fontan model, and 0.1–0.3 cm3 and 0.1–0.6 cm2 in the TCPC Fontan model. The SR and WSR increased in the APC model with a normal-sized RA and the TCPC model as the flow rate of blood from the inferior vena cava increased with exercise; however, the SR and WSR in the RA decreased in the APC model with a dilated RA owing to the development of a recirculating flow. These findings suggest that the APC Fontan has a higher risk of thrombosis due to blood stasis than the TCPC Fontan and a higher RA dilation is associated with a higher risk of thrombosis from a fluid mechanics perspective.

Recapitulation of single ventricle haemodynamics and associated interplay with breathing mechanics using clinically validated multimodal simulators

“…To demonstrate the usability of this biomimetic Fontan simulator as a test platform for device evaluation, we implanted a one-way valve in the benchtop simulator to support Fontan haemodynamics as previously suggested in the literature 7,32,[49][50][51] . To characterize the risks associated with implanted devices, a detailed haemodynamic assessment of blood flow and its interaction with the device is essential in addition to organ level flow evaluations 35,52,53 . Towards this goal, we developed a computational fluid dynamics model of the Fontan IVC which reproduces the flow conditions of the benchtop simulator and allows for the analysis of fluid-solid interactions between potential support strategies and blood.…”