Influence of stent edge angle on endothelialization in an in vitro model

PURPOSE: To investigate the influence of topographic features in the path o f migrating endothelial cells, specifically the effect of edge angle of int ravascular metallic material on endothelialization. MATERIALS AND METHODS: Flat l-cm x l-cm 316-L pieces of stainless steel wer e placed on confluent monolayers of human aortic endothelial cells. The thi ckness of each metal piece was ground to achieve an edge angle of 35 degree s, 70 degrees, 90 degrees, or 140 degrees (n = 6 each) in relation to the e ndothelial surface. Migration distance and density of endothelial cell cove rage on the metal pieces were measured in groups of six each under static c onditions at 4, 7, and 11 days and flow conditions (16 dynes/cm(2)) at 4 da ys. RESULTS: Endothelial cell migration distance along the surface of the piece s with edge angles of 35 degrees was significantly greater than that with t hose with larger angles (P < .05) under static and flow conditions. The mig ration distances on the 35 degrees piece were 87.5%, 47.3%, 57.1%, and 66.1 % greater than those on the 90 degrees piece at the upstream, downstream, r ight, and left edges, respectively. There were no significant differences i n cell density among different angle groups under flow or static conditions . CONCLUSION: The edge angle of intravascular metallic material has an influe nce on the rate of endothelialization. A smaller edge angle facilitates end othelialization over metallic material when compared to a larger angle. The se results demonstrate the importance of metallic stent profile on endothel ialization rate.