Webbing and Delamination of Drug Eluting Stent Coatings.
The advancement of the drug-eluting stent technology raises the significant challenge of safe mechanical design of polymer coated stent systems. Experimental images of stent coatings undergoing significant damage during deployment have been reported; such coating damage and delamination can lead to complications such as restenosis and increased thrombogenicity. In the current study a cohesive zone modeling framework is developed to predict coating delamination and buckling due to hinge deformation during stent deployment. Models are then extended to analyze, for the first time, stent-coating damage due to webbing defects. Webbing defects occur when a bond forms between coating layers on adjacent struts, resulting in extensive delamination of the coating from the strut surfaces. The analyzes presented in this paper uncover the mechanical factors that govern webbing induced coating damage. Finally, an experimental fracture test of a commercially available stent coating material is performed and results demonstrate that the high cohesive strength of the coating material will prevent web fracture, resulting in significant coating delamination during stent deployment.
Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland.
C
C
Hopkins
Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland.
C A
CA
Sweeney
Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland.
C
C
O'Connor
Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland.
P E
PE
McHugh
Biomedical Engineering, College of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland. patrick.mcgarry@nuigalway.ie.
J P
JP
McGarry
D020099:Coated Materials, Biocompatible; D054855:Drug-Eluting Stents; D019544:Equipment Failure Analysis; D006801:Humans; D008962:Models, Theoretical; D011474:Prosthesis Design
D020099:Coated Materials, Biocompatible
Buckling; Coating; Cohesive zone modeling; Delamination; Drug eluting stent; Webbing