Introduction: Computational Fluid Dynamics (CFD) modelling is increasingly used to study peripheral artery disease (PAD). However, most CFD models do not account for the global impact of PAD, particularly downstream perfusion, the degree of lower limb ischaemia, and the role of collateral flow.
This study aims to develop and validate a one-dimensional (1D) arterial network model of the lower limb, incorporating collateral pathways, to study the haemodynamic effects of PAD and the role of collateral circulation.
Methods: An existing 116-artery 1D model of pulsatile blood flow in the systemic circulation, validated at the population level for individuals aged 25–75 years, was extended to include the profunda femoris collateral pathway, resulting in a 130-artery model. The new model was calibrated and validated using clinical data from the literature. Different PAD lesion types and severities were simulated by modifying vessel geometry and material properties in the lower limbs. Pressure, flow velocity and luminal pulse waves were computed upstream and downstream of stenoses and qualitatively compared with corresponding in vivo waveforms.
Results: Under healthy conditions, the simulated pulse waveforms in the upper body showed less than 1% root mean square error compared to the original 116-artery model. In the lower limbs, the new model produced results qualitatively consistent with clinical data. For all PAD types, blood perfusion and pressure decreased as stenosis severity increased. Critical stenosis thresholds for each PAD type were identified, and the role of collateral pathways was evaluated.
Conclusion: The improved 1D modelling offers a computationally efficient approach to studying the haemodynamics of different PAD types without compromising accuracy. Future work will focus on applying this model to surgical planning for stent implantation.