Influence of topography on endothelialization of stents: clues for new designs.

To evaluate the influence of stent design on endothelialization of the stented surface, we placed trapezoidal objects of variable thickness on a confluent culture of endothelial cells and subjected the assembly to flow and shear conditions similar to those found in arteries. After 24 h, we measured and analyzed the area on top of the objects covered by cells and the maximum migration distance from the borders. In addition, we evaluated areas devoid of cells surrounding the objects, which developed after exposure of the assembly to flow. The cell-covered area and migration distance significantly decreased on objects 75 microns thick, and it was nonexistent on objects 250 microns thick. Areas devoid of cells or gaps were largest adjacent to the downflow side of the object, disposed transversely to flow. Cell gaps were smallest along the side aligned with flow. In conclusion, endothelial cell coverage may be impaired by stent wall thickness larger than 75 microns. It is likely that this impairment is related to flow disturbances impairing cell attachment.