Polymer coated guidewire
A guidewire or section thereof, that has a core member or the like with a plurality of contiguous tapered segments having taper angles that are configured to produce a linear change in stiffness over a longitudinal portion of the device. The device may also have a core section with a continuously changing taper angle to produce a curvilinear profile that is configured to produce a linear change in stiffness of the core over a longitudinal portion of the device. An embodiment has a plurality of radiopaque elements that may be intermittent, continuous or in the form of a helical ribbon for scaled measurement of intracorporeal structure under fluoroscopic imaging. Another embodiment has at least one layer of polymer over the distal end of the device.
1. A guidewire comprising:
an elongated core member having a proximal section and a distal section with a plurality of radiopaque markers disposed thereon at regular intervals in axial position and a longitudinal portion which tapers distally to a reduced transverse dimension wherein the taper creates a substantially linear change in stiffness of the core member over a length thereof;
a flexible body member disposed about the distal section of the elongate core member; and
a polymer layer disposed about at least a portion of the distal section of the elongate core member and the flexible body member.
2. The guidewire of claim 1 wherein the polymer layer is selected from a group consisting of polyurethanes, polyamide, copolymers of polyurethane and copolymers of polyamide.
3. The guidewire of claim 1 wherein the polymer layer has a substantially constant outer diameter.
4. The guidewire of claim 1 wherein the longitudinal portion has a length of about 5 to about 25 cm.
5. The guidewire of claim 1 wherein the longitudinal portion has a curvilinear taper over a length thereof.
6. The guidewire of claim 1 wherein the radiopaque markers are made of a radiopaque metal secured to the distal section of the elongate core member.
7. The guidewire of claim 6 wherein the radiopaque metal for the radiopaque markers is selected from the group consisting of gold, platinum, platinum-iridium, tantalum and tungsten.
8. The guidewire of claim 1 wherein the markers are made of a radiopaque matrix applied to the distal section of the elongate core member.
9. The guidewire of claim 8 wherein the radiopaque matrix comprises a radiolucent polymer doped with a radiopaque material.
10. The guidewire of claim 9 wherein the radiolucent polymer comprises polyurethane.
11. The guidewire of claim 9 wherein the radiopaque material comprises tungsten powder.
12. A guidewire comprising:
an elongated core member having a proximal section and a distal section with a plurality of radiopaque markers disposed thereon at regular intervals in axial position and a longitudinal portion which tapers distally to a reduced transverse dimension wherein the taper creates a substantially linear change in stiffness of the core member over a length thereof;
a helical coil disposed about the distal section of the elongate core member; and
a polymer layer disposed about at least a portion of the distal section of the elongate core member and at least partially enveloping the helical coil, wherein the polymer layer has a substantially constant outer diameter.