Guidewire stiffness: what's in a name?

PurposeTo measure the stiffness of commonly used “stiff” guidewires in terms of their flexural modulus, an engineering parameter related to bending stiffness.MethodsEleven different intact stiff guidewires were selected to undergo a 3-point bending test performed using a tensile testing machine. Testing was performed on 3 new and intact specimens of each guidewire at 10 locations along the wire's length, excluding the floppy tip. The flexural modulus (in gigapascals, GPa) was calculated from the results of the bending test.ResultsThe flexural modulus of the plain Amplatz wire was 9.5 GPa compared to 11.4 to 14.5 GPa for the “heavy duty” wires. Within the Amplatz family of guidewires, the flexural modulus was 17 GPa for the “stiff,” 29.2 GPa for the “extra stiff,” 60.3 GPa for the “super stiff,” and 65.4 GPa for the “ultra stiff.” The Backup Meier measured 139.6 GPa and the Lunderquist Extra Stiff 158.4 GPa.ConclusionThe Instructions for Use of some endovascular devices specify a wire type selected from a ...