Blood flow repartition in distensible microvascular networks: Implication of interstitial and outflow pressure conditions

This paper examines the behavior of microvascular networks subjected to the coupled action of external (interstitial) and luminal pressure loads and under a prescribed inlet/outlet pressure drop. A network of 1D distensible tubes is used to represent microcirculatory districts. The thin shell theory is used to compute the geometry of the deformed tube section under the pressure loads. Blood flow and pressure drop in each tube are then related through a generalized Ohm's law featuring a conductivity parameter, function of the area and shape of the tube cross section. The model is used to study the response of representative arterial and venous bifurcations for different external and outlet pressures. Several features of the system response due to the interaction of the vessels of the network emerge from the simulations. Flow plateau, choking and flow diversion from one branch of the system to the other arise when buckling occurs. These results highlight the importance of considering the network connectivity along with the geometrical and mechanical characteristics of the vessels.