A Smart Guidewire for Smooth Navigation in Interventional Radiology

Objective: To design and manufacture a smart guidewire using nitinol materials, as well as evaluated the device functionality, such as bending performance, trackability, thermal effects, and thrombogenic response.

Methods: Two types of nitinol material were partially used to enhance the guidwire trackability.  A proposed smart guidewire system uses either one- or two-way shape-memory alloy nitinol (1W-SMA, 2W-SMA) wires (0.015”, 381μm nitinol wire, NCD, CA, USA). Bending stiffness was measured using in vitro test system, which contains the NI USB-9162 data logger and LabViewTM Signal Express 2010 (National Instruments, TX, USA). Temperature distribution and displacement were evaluated via recording a 60Hz movie using a SC325 camera (FLIR Systems, Australia). Hemocompatibility was evaluated by scanning electron microscopy after one heating cycle of nitinol under the Na-citrate porcine whole blood (Lampire Biological Lab., PA, USA) circulation.

Results: Prototypes have been successfully developed and tested. A smart guidewire showed 30 degrees bending after applying or disconnecting electrical current. While the temperature of the nitinol wires increased more than 70°C, the surrounding temperature with the commercially available catheter coverings showed below human body temperature showing 30~33°C. There was no significant platelet attachment or blood coagulation when the guidewire operates.

Conclusion: Novel smart guidewires have been developed using shape memory alloy nitinol, which may represent a novel alternative to typical commercially available guidewires for interventional procedures.