Computer model of nucleotide transport in a realistic porcine aortic trifurcation

Adenosine triphosphate (ATP) is a ubiquitous blood borne agonist which is responsible for the regulation of vascular tone via purinogenic signalling pathways. The present study models the transport of ATP in a realistic porcine aortic trifurcation, which includes multiple branches and bifurcations. The focus of the present study is understanding how pulsatile flow effects mass transfer, observing both mean and transient variations. Unlike in the many idealized models which model transport of low diffusion coefficient species, the realistic geometry leads to very different mass transfer characteristics. These include spiral patterns in the distribution of low concentration fluid. Furthermore, the mean ATP distribution was found to be elevated compared with the steady state; this is attributed to the effects of convective mixing. The results strongly implicate that under certain conditions mass transport in pulsatile flow exhibits different hydrolysis characteristics at the endothelium compared with steady state. Transient variations throughout the the cardiac cycle were found to be small. This small transient response is primarily due to low ATP diffusivity.