HIGH TORQUE GUIDEWIRE DEVICE
Disclosed is a guidewire configured to provide high torsional stiffness without detrimentally increasing bending stiffness. Such a device provides a high ratio of torsional stiffness to bending stiffness. The guidewire device includes a core with a proximal section and a distal section. The distal section of the core is coupled to a microfabricated outer tube such that the distal section of the core passes into and is encompassed by the outer tube.
1 . A guidewire device configured to provide high rotational stiffness without significantly increasing bending stiffness, the guidewire comprising:
a core including a proximal section and a distal section; and
a microfabricated outer tube coupled to the core such that the distal section of the core passes into and is encompassed by the outer tube,
wherein the outer tube and the core define an annular space between an inner surface of the outer tube and an outer surface of the distal section of the core, the device further comprising, within the annular space
a distal coil encompassing part of the distal section of the core;
a proximal coil disposed proximal of the distal coil and encompassing part of the distal section of the core; and
a bushing coil disposed over at least a portion of the distal coil and over at least a portion of the proximal coil.
2 . The guidewire device of claim 1 , wherein an outer diameter of the outer tube is greater than an outer diameter of the proximal section of the core.
3 . The device of claim 2 , wherein the outer diameter of the outer tube is larger than the outer diameter of the proximal section of the core by about 10% or more.
4 . The guidewire device of claim 1 , wherein the distal coil is more radiopaque than stainless steel.
5 . The device of claim 4 , wherein the proximal coil is less radiopaque than the distal coil.
6 . The device of claim 1 , wherein the bushing coil extends farther proximally than the proximal coil.
7 . The device of claim 6 , wherein the bushing coil has a length of at least about 60% of the length of the outer tube.
8 . The device of claim 1 , wherein at least one of the proximal coil, distal coil, and bushing coil is wound in a direction opposite the other coils.
9 . The device of claim 1 , wherein the bushing coil has a pitch that is smaller than that of the proximal coil and/or distal coil.
10 . The device of claim 1 , wherein the proximal coil, distal coil, and bushing coil fill 15% or more of the volume of the annular space.
11 . The device of claim 1 , wherein the device has a ratio of rotational stiffness to bending stiffness of 160 m −1 ·rad −1 or greater at a location 0.5 cm from a distal end of the device.
12 . The device of claim 1 , wherein the device has a ratio of rotational stiffness to bending stiffness of 80 m- −1 ·rad −1 or greater at a location 1.0 cm from a distal end of the device.
13 . The device of claim 1 , wherein the device has a ratio of rotational stiffness to bending stiffness of 130 m −1 ·rad −1 or greater at a location 1.5 cm from a distal end of the device.
14 . The device of claim 1 , wherein the device has a ratio of rotational stiffness to bending stiffness of 50 m −1 ·rad −1 or greater at a location 2.0 cm from a distal end of the device.
15 . The device of claim 1 , wherein the device has a ratio of rotational stiffness to bending stiffness of 15 m −1 ·rad −1 or greater at a location 5.0 cm from a distal end of the device.
16 . The device of claim 1 , wherein the device has a ratio of rotational stiffness to bending stiffness of 8 m −1 ·rad −1 or greater at a location 8.0 cm from a distal end of the device.
17 . A guidewire device configured to provide high rotational stiffness without significantly increasing bending stiffness, the guidewire comprising:
a core including a proximal section and a distal section;
a microfabricated outer tube coupled to the core such that the distal section of the core passes into and is encompassed by the outer tube;
a distal coil encompassing part of the distal section of the core;
a proximal coil disposed proximal of the distal coil and encompassing part of the distal section of the core; and
a bushing coil disposed over at least a portion of one or both of the distal coil and the proximal coil,
wherein the outer tube and the core define an annular space between an inner surface of the outer tube and an outer surface of the distal section of the core and wherein the proximal coil, distal coil, and bushing coil fill 15% or more of the volume of the annular space,
wherein an outer diameter of the outer tube is greater than an outer diameter of the proximal section of the core by about 10% or more,
18 . The device of claim 17 , wherein the bushing coil extends farther proximally than the proximal coil.
19 . The device of claim 17 , wherein the bushing coil has a length that is at least 60% of a length of the outer tube.
20 . The device of claim 17 , wherein the proximal coil is less radiopaque than the distal coil.