Foot perfusion. Insights from an anatomically detailed arterial network model

Peripheral artery disease currently affects over 202 million people worldwide. The ankle-brachial index is one of the most used measurements to assess a reduction in blood flow to the foot, but it is not able to characterise tissue perfusion. Information on tissue perfusion can be obtained, among others, through an MRI scan, which is time-consuming and can be painful if induction of ischemia is warranted for the scan. As an alternative, we model foot perfusion during a cuff-induced ischaemia test to characterise how occlusions in foot arteries affect perfusion in foot regions. Simulations are not patient-specific at this stage, and are conducted on a 1D arterial network model which includes 154 foot and calf arterial segments, providing a realistic description of the topology of the foot arterial vasculature. A baseline model characterizes perfusion in angiosomes under healthy conditions, which is then modified to reflect 42 pathological scenarios by introducing occlusions and different levels of collateral impairment. Results show a marked influence of collateral impairment on angiosome perfusion under the condition of a single-artery occlusion, highlighting the role of blood redistribution. If two feeding arteries are occluded, perfusion markedly decreases at all collateral impairment levels due to the severe reduction in incoming blood flow. These results provide a bridge between the angiosome-targeted and “best-vessel” strategies for revascularization, showing that both can be correct depending on collateral sufficiency. Graphical Abstract Highlights We propose a computational model of foot perfusion during a cuff-induced ischaemia test that allows the assessment of perfusion in each angiosome of the foot We study how occlusions in the main feeding arteries of the foot impact tissue perfusion We highlight the role of collateralization if adequate inflow is maintained Results show that both angiosome-targeted and “best-vessel” strategies for revascularization can be correct depending on arch patency and collateral sufficiency