NiTi Thin Film Technology for Endovascular Applications

The application of thin film technology in the field of endovascular devices, such as filters, stents and grafts, has been hampered i.a. by the limitation of film thickness and the lack of mechanical and fatigue performance data. Recent data confirmed that microstructured NiTi thin films can be reliably produced up to 80µm thickness, allowing the fabrication of novel, complex geometries as well as adding new functionalities. 

Based on neurovascular stent designs, prototypes have been fabricated by means of magnetron sputtering, UV lithography and chemical etching. These are compared with conventional manufactured stents. Furthermore, novel strut geometries available with thin film technology were produced.             
Mechanical fatigue behaviour and surface properties were investigated in vitro. Superior mechanical and fatigue behaviour have been observed compared to conventional Nitinol devices, suggesting an enhanced delivery through microcatheters and an improved expansion and vessel apposition under pulsatility. A first in vivo evaluation of thrombogenicity, vessel patency and endothelialisation was also performed.

The possibility to obtain complex microstructured geometries using thin film technology opens a wide range of applications in the endovascular field. Moreover, it promises a significant future potential for manufacturing devices in other biomedical areas as well, e.g. neurostimulation, electrophysiology and cardiac rhythm management.