Effects of arterial bifurcation geometry on nucleotide concentration at the endothelium

A mathematical and computational analysis of nucleotide concentration for a two-dimensional artery bifurcation has been developed. This region of the vasculature is known to be exposed to spatially varying wall shear stress (WSS), hence the variation of adenosine nucleotides is of interest. A previously derived similarity solution for mass transport in blood boundary layers for arbitrary wall shear stress function has been used. For the analytical model, the geometric condition has been incorporated into the system using the theory for flow past a wedge. As the bifurcation angle varies different characteristics are exhibited, such as maxima in ADP concentration and the existence of a low wall shear stress region around the stagnation point, for large angles. In the limiting case of two-dimensional stagnation point flow the concentration was constant throughout the domain length. The computational simulations provided a more detailed understanding into how nucleotides vary. Similarities existed between the two solution methods in the vicinity of the stagnation point, but deviated as the fully developed condition prevailed. Additionally, the effect of pulsatile flow has been included, leading to considerable gradients in wall shear stress, both temporal and spatial. However, the resulting nucleotide concentration is determined by the time-averaged wall shear stress. The effects of flow-induced ATP release have also been included, leading to significant changes in ATP concentration. Under rapid release, the concentration at the surface increased relative to the bulk concentration.