| 摘要 |
A composite guidewire 10 includes a central core 12 that is made out of a "linear elastic" material, which at body temperature does not exhibit a yield point and/or change phase when subjected to the range of stresses that are common to guidewires. A core extension 30, which is made out of stiffer material, such as stainless steel, attaches to the central core through a coupling tube, which may be made of super elastic material, linear elastic material, or stainless steel. The coupling tube 16 fits over a tapered distal end of the core extension and a proximal end of the central core that may but need not be tapered. The proximal end of the coupling tube abuts the tapered section of the core extension where the section has an outer diameter that is approximately the same size as the inner diameter of the coupling tube, and the tube is thus held against axial movement. The space between the inner diameter of the coupling tube and the ends that fit within the tube are filled with an adhesive, to create a strong yet flexible joint that transmits considerable torque without failure. An elongated coil 18, which may be radiopaque, fits over the distal portion of the central core. The coil may attach at a proximal end to the distal end of the coupling tube by, for example, adhesive, brazing or welding, such that the coil and the coupling tube provide support for the linear elastic core along the entire length of the core. The coil may instead extend over the coupling tube, such that the coil attaches to the distal end of the core extension. A shaping ribbon 20 which is made of bendable material, such as, for example, stainless steel, is attached to a distal portion of the central core and extends beyond the end of the core, to provide a shapeable distal end to the guidewire. An atraumatic tip 26 fits over the end of the guidewire and attaches to the coil and the shaping ribbon by brazing, welding or adhesive, to provide a cushioned end to the guidewire. As appropriate, a relatively short radiopaque outer coil may be positioned over the elongated coil, to provide visibility to the distal end of the guidewire. <IMAGE>
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