The development of a model of the femoral artery bifurcation for use with duplex Doppler systems

The ability to reproduce physiologic blood flow characteristics in vitro, combined with the ability to extract data using duplex Doppler ultrasound (US), is a desirable characteristic in a model of the femoral artery. This would allow duplex Doppler measurement protocols to be studied and developed on a realistic and repeatable platform. This paper describes the development and limitations of a model with these design specifications. The model features pulsatile pressure and flow, a source impedance and compliant vessels including bifurcations. The effects of bifurcation angle on the volume flow division ratio between the superficial femoral and the profunda femoris sections of the model were measured using a transit time flowmeter. No significant dependence on bifurcation angle was detected. Duplex Doppler US was also used to measure the volumetric flow in each arm of the bifurcation. Readings were compared with the transit time flowmeter. Measurements were overestimated by approximately 30% in the profunda femoris and underestimated by approximately 20% in the superficial femoral sections of the model. These errors were larger than those predicted by other theoretical studies. The model has been shown to be a useful platform on which to perform haemodynamic simulations. The model demonstrated that bifurcation angle does not influence the volumetric flow in the downstream arteries. Volumetric flow measurements using duplex Doppler US are erroneous around the bifurcation and need to be treated with great care. The model shows excellent potential to be a useful tool in duplex Doppler-based studies.