Swirling flow can suppress monocyte adhesion in the flow disturbance zones of the endovascular stent

Adhesion of monocytes (U-937 cells) along a silicone tube deployed with circular ring stents was studied to test the hypothesis that by intentionally inducing swirling flow in an endovascular stent, the adhesion of monocytes would be suppressed. The results revealed that under a normal flow condition, the flow disturbance created by the circular ring stents enhanced the adhesion of U-937 cells in the silicone tube. By inducing a swirling flow in the silicone tube, the average wall shear stress (WSS) in the tube with the circular ring stents was elevated and significantly suppressed the adhesion density of U-937 cells to the surface in the disturbed flow zones to a level equal to that when no stents were deployed in the tube. The results also showed that, due to the attenuation of the swirling flow along the tube, the adhesion density of U-937 cells increased monotonically along the tube, indicating that the adhesion density was negatively correlated with the strength of the swirling flow. Thus, the present study suggests that intentionally introducing swirling flow in an artery deployed with stents may be a solution to solve the problem of stent restenosis by restraining the adhesion of monocytes.