Local Hemodynamics in Coronary Bypass in the Presence of Competitive Flow and Different Diameter Ratios Between Graft and Host Artery

Coronary bypass graft patency is strongly influenced by local hemodynamics in the anastomosis region. Graft failure is mainly caused by intimal hyperplasia development which is associated to low values of Wall Shear Stress (WSS). Several factors are known to alter the local hemodynamic environment, such as: type of graft, suture configuration, anastomosis angle, ratio between graft and native artery diameters and the presence of competitive flow. The aim of this paper was to analyze the influence of competitive flow on local hemodynamics at the anastomosis region in bypass configurations with different ratio between graft and native stenosed artery diameters, for a coronary stenosis of 75%. The results indicated that the most significant flow alterations and WSS variation occur at the anastomosis site and are strongly influenced by the presence of the fluid jet through the partially stenosis in case of competitive flow. Graft diameter influences these hemodynamic alterations to a further extent, especially when coupled with the negative effects of competitive flow. These findings provide a better understanding of the phenomena that occur in the bypass anastomosis region and may potentially contribute to the improvement of the coronary bypass surgical approach in order to increase long-term graft patency.