The first step to understanding how to use a guidewire is to know the engineering aspects of wire technology, core material, and how different components change the wire’s characteristics. Guidewires are comprised of mainly four features: core, tip, body, and coating. The small variations in these components have drastic impacts on guidewire characteristics and their intended application. The areas that differentiate over a hundred guidewire are mainly due to various compositions at the wire’s distal end.
- Core: It is the stiffest and innermost part of the wire. It provides stability and steerability and extends through the wire’s shaft from the proximal to the distal portion where it tapers.
- Core Material: The core is usually made of stainless steel, which provides excellent support with excellent torque transmission but is less flexible and not kink resistant. On the other hand, nitinol core, a super-elastic alloy of nickel and titanium, has more flexibility, excellent resiliency, and kink resistance. Newer wires (hybrid type) are made of stainless steel and nitinol distal tip for better torque transmission and excellent flexibility with kink resistance. (I.e. Runthrough, Minamo, Maestro, Spectre)
- Core Diameter: It is the part of the wire that tapers to the tip, not the wire’s overall size, and determines the flexibility (smaller diameter) and support (larger diameters).
- Core Taper: This is the part of the wire that extends from the core to the tip. The ability to transmit torque depends on the taper’s length; shorter tapers tend to prolapse but provide more support, while longer tapers offer less support but track successfully.