Thin Film Nitinol Microstent for Aneurysm Occlusion

This film nitinol produced by sputter deposition was used in the design of microstents intended to treat small vessel aneurysms. Thin film microstents were fabricated by “hot-target” DC sputter deposition. Both stress-strain curves and DSC curves were generated for the film used to fabricate stents. The films used for stents had an A_f temperatures of approximately 36 degrees allowing for body activated response from a micro-catheter. The ten micron film was only slightly radio-opaque; thus, a Td marker was attached to the stents to guide fluoroscopic delivery. Thin film microstents were tested in a flow loop with and without nitinol support skeletons to given additional radial support. Stents could be compressed into and easily delivery in < 3 Fr catheters. Theoretical frictional and wall drag forces on a thin film nitinol small vessel vascular stent were calculated and the radial force exerted by thin film stents was evaluated theoretically and experimentally. In-vivo studies in swine confirmed that thin film nitinol microstents could be deployed accurately and consistently in the swine cranial vasculature.