Simulation of flow and shear stress

The evaluation of wall shear stress (WSS) patterns in vivo using computational fluid dynamic (CFD) methods has revealed the important role of WSS distribution in the natural history of atherosclerotic lesion development [1-5]. Low and oscillating WSS are now known to modulate arterial wall biology and in particular endothelial cell function through complex mechano-transduction pathways that regulate gene expression and plaque biology [6,7]. Low WSS has been shown to set the arterial lining cells in a pro-inflammatory mode which accelerates the formation of vulnerable atherosclerotic plaques [6,7]. In stented segments several studies have demonstrated that WSS affects neointima tissue development [8-12]. In particular it has been shown that in bare metal stents the local hemodynamic milieu determines neointima proliferation while in drug eluting stents this effect is attenuated by the antiproliferative drug and it is more obvious in paclitaxel eluting stents than in sirolimus eluting devices [12] (Figures 3.4.1 and 3.4.2).