Numerical simulation on the effects of drug-eluting stents with different bending angles on hemodynamics and drug distribution.

Implantation of drug-eluting stents in curved blood vessels may cause changes in hemodynamics and drug distribution, and even provoke in-stent restenosis. Due to the complexity of building three-dimensional (3-D) curved stent model, few studies have gone through such numerical simulations. In this study, three virtual stent models with different bending angles (0°, 30° and 90°) were developed to numerically investigate the distribution of wall shear stress (WSS) and drug concentration. The results showed that (1) the low-WSS regions in the inner bend of the stent models increased with the bending angles; (2) the drug concentration differed between the inner and outer bends of the stents but irrespective to the changes of bending angle; (3) the pattern of drug concentration for the curved stents found similar to that of the straight stents, and the phenomenon, 'proximal part low and distal part high' in the drug concentration showed in both the straight and curved stents. The increase in bending angles from 30° to 90° had little effect on the WSS and drug concentration; however, the largest effect of the curved stents was the remarkable difference of drug concentration between the inner and outer bends of the stents-about 20 %. Hence, it is feasible that quick analysis focused on the straight stents instead of the curved stents.