Haemodynamic analysis of femoral artery bifurcation models under different physiological flow waveforms.

Thrombus in a femoral artery may form under stagnant flow conditions which vary depending on the local arterial waveform. Four different physiological flow waveforms - poor (blunt) monophasic, sharp monophasic, biphasic and triphasic - can exist in the femoral artery as a result of different levels of peripheral arterial disease progression. This study aims to examine the effect of different physiological waveforms on femoral artery haemodynamics. In this regard, a fluid-structure interaction analysis was carried out in idealised models of bifurcated common femoral artery. The results showed that recirculation zones occur in almost all flow waveforms; however, the sites at where these vortices are initiated, the size and structure of vortices are highly dependent on the type of flow waveform being used. It was shown that the reverse diastolic flow in biphasic and triphasic waveforms leads to the occurrence of a retrograde flow which aids in 'washout' of the disturbed flow regions. This may limit the likelihood of thrombus formation, indicating the antithrombotic role of retrograde flow in femoral arteries. Furthermore, our data revealed that the flow particles experience considerably higher residence time under blunt and sharp monophasic waveforms than under biphasic and triphasic waveforms. This confirms that the risk of atherothrombotic plaque initiation and development in femoral arteries is higher under blunt and sharp monophasic waveforms than under biphasic and triphasic flow waveforms.