Adaptive Coil Guidewire

Abstract

The elongate medical device (10) is configured to provide adjustable flexibility. The elongate medical device includes an inner coil (28) having one or more inner coil filers (32) extending in a first direction and an outer coil (30) having one or more outer filers (34) extending in a second direction. A hypotube (26) extends proximally from the inner coil and the outer coil. A cable (50) extends through the inner coil and the hypotube, with a distal end of the cable, a distal end of the inner coil, and a distal end of the outer coil all secured together at a distal end of the elongate medical device, and applying a tension force to the cable relative to the hypotube increases the stiffness of the inner coil and outer coil combination.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to medical devices and methods for making and using medical devices. [Background technology]

[0002] FIELD OF THE DISCLOSURE The present disclosure relates to medical devices and methods for manufacturing medical devices. More particularly, the present disclosure relates to intracorporeal medical devices and methods for manufacturing and using such devices. Known medical devices and methods each have certain advantages and disadvantages. Summary of the Invention

[0003] The present disclosure provides design, material, manufacturing, and usage alternatives for medical devices. In one example, an elongate medical device is configured to provide adjustable flexibility. The elongate medical device includes an inner coil having one or more inner coil filers extending in a first direction at an inner coil angle, the inner coil having an outer diameter; and an outer coil having one or more outer filers extending in a second direction opposite the first direction at an outer coil angle, the outer coil having an inner diameter, the outer coil having one or more outer filers extending in a second direction opposite the first direction at an outer coil angle, the inner diameter of the outer coil being substantially equal to the outer diameter of the inner coil, and the inner coil angle being substantially equal to the outer coil angle. A hypotube extends proximally from the inner coil and outer coil, the proximal end of the inner coil and the proximal end of the outer coil being secured to the distal end of the hypotube. A cable extends through the inner coil and the hypotube, the distal end of the cable, the distal end of the inner coil, and the distal end of the outer coil are all secured together at the distal end of the elongate medical device. Applying tension to the cable against the hypotube increases the stiffness of the inner and outer coil combination.

[0004] Alternatively or additionally, the one or more inner coil filers may have a wire size and the one or more outer coil filers may have the same wire size. Alternatively or additionally, the inner coil may have multiple filers and the outer coil may have the same number of filers.

[0005] Alternatively or additionally, the inner diameter of the outer coil may be within about 5 percent of the outer diameter of the inner coil. Alternatively or additionally, the inner diameter of the outer coil may be within about 1 percent of the outer diameter of the inner coil.

[0006] Alternatively or additionally, the distal end of the inner coil, the distal end of the outer coil, and the distal end of the cable may all be welded together. Alternatively or additionally, the proximal end of the inner coil and the proximal end of the outer coil may be welded together and to the distal end of the hypotube.

[0007] As another example, an elongate medical device includes a distal segment configured to provide adjustable flexibility and a proximal segment defining an elongate shaft. The distal segment includes an inner coil having one or more inner coil filers extending in a first direction at an inner coil angle, an outer coil having one or more outer coil filers extending in a second direction opposite the first direction at an outer coil angle substantially equal to the outer coil angle, and a cable extending through the inner coil and extending proximally from the inner coil, the distal end of the cable being welded together to the distal end of the inner coil and the distal end of the outer coil. The distal end of the elongate shaft is welded to the proximal end of the inner coil and the proximal end of the outer coil. The distal segment is configured to increase in stiffness when tension is applied to the cable.

[0008] Alternatively or additionally, the inner coil has an outer diameter and the outer coil has an inner diameter approximately equal to the outer diameter of the inner coil. Alternatively or additionally, the outer diameter of the inner coil may be within about 5 percent of the inner diameter of the outer coil.

[0009] Alternatively or additionally, the outer diameter of the inner coil may be within about 1 percent of the inner diameter of the outer coil. Alternatively or additionally, the inner coil may have multiple filers and the outer coil may have the same number of filers.

[0010] Alternatively or additionally, each of the one or more inner coil filers has a wire diameter and each of the one or more outer coil filers has the same wire diameter. Alternatively or additionally, the elongate shaft may include a hypotube.

[0011] As another example, a guidewire includes a coil assembly including an inner coil having one or more inner coil filers extending in a first direction and an outer coil having one or more outer coil filers extending in a second direction, the inner coil having an outer diameter substantially equal to the inner diameter of the outer coil. A cable has an attachment point connecting together a distal end of the inner coil and a distal end of the outer coil, the cable extending freely in a proximal direction from the attachment point. The cable is configured to provide a compressive force to the coil assembly, thereby temporarily increasing the stiffness of the coil assembly.

[0012] Alternatively or additionally, the one or more inner coil filers may extend at a coil angle and the one or more outer coil filers may extend at the same coil angle. Alternatively or additionally, the outer diameter of the inner coil may be within about 5 percent of the inner diameter of the outer coil.

[0013] Alternatively or additionally, the outer diameter of the inner coil may be within about 1 percent of the inner diameter of the outer coil. Alternatively or additionally, the inner coil may have multiple filers and the outer coil may have the same number of filers.

[0014] Alternatively or additionally, each of the one or more inner coil filers may have a wire diameter and each of the one or more outer coil filers may have the same wire diameter. The above summary of some embodiments is not intended to describe each disclosed embodiment or every implementation of the present invention, and the following figures and detailed description further exemplify these embodiments. [Brief explanation of the drawings]

[0015] The present invention can be better understood by considering the following detailed description of the invention in conjunction with the accompanying drawings. [Figure 1] 1 is a schematic side view of an exemplary elongate medical device. [Figure 2] FIG. 2 is a side view of the exemplary elongate medical device of FIG. 1 without an outer polymeric layer. [Figure 3] FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. [Figure 3A] FIG. 1 is a schematic cross-sectional view illustrating another embodiment of the present disclosure. [Figure 4] 2 is a side view of an outer coil forming part of the exemplary elongate medical device of FIG. 1. [Figure 5] 2 is a side view of an inner coil forming part of the exemplary elongate medical device of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0016] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and have been described in detail. It is not, however, intended to limit the disclosure to the particular embodiments described. Rather, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

[0017] For the following defined terms, these definitions shall be used unless a different definition is given in the claims or the specification. All numerical values ​​herein are assumed to be modified by the term "about," whether expressly stated or not. The terms "approximately" or "about" refer to a range that one of ordinary skill in the art would consider to perform an equivalent function or effect. In many instances, the term "about" includes numerical values ​​that are rounded to the nearest significant figure.

[0018] When numerical ranges are recited by endpoints, it is intended to include all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0019] As used herein and in the appended claims, the singular forms "a," "an," "the," etc., include plural referents unless the context clearly dictates otherwise. Also, as used herein and in the appended claims, "or" is used in the sense of "and / or" unless the context clearly dictates otherwise.

[0020] The following detailed description should be read with reference to the drawings, in which similar elements in different drawings are numbered the same, and which, although not necessarily to scale, illustrate embodiments and are not intended to limit the scope of the present invention.

[0021] A guidewire may be used, for example, to pass through various portions of a patient's vasculature. In some cases, a guidewire may be used, for example, to pass through internal structures within an organ. It will be appreciated that a guidewire may have conflicting performance requirements. For example, a guidewire, or portions thereof, may be required to be highly flexible to pass through highly tortuous paths. For example, a guidewire, or portions thereof, may be required to be stiff to aid in pushing the guidewire through obstacles. Torque transmission is another example of a guidewire performance characteristic. It will be appreciated that these characteristics, particularly flexibility and stiffness, are mutually exclusive. A highly flexible guidewire lacks stiffness. A stiff guidewire lacks flexibility. Some guidewires have regions designed to be flexible and other regions designed to be stiff, but these characteristics are set at the factory and are not adjustable. FIG. 1 shows an example of a guidewire that is flexible but can be temporarily stiffened as desired.

[0022] FIG. 1 is a schematic side view of an exemplary guidewire 10. The exemplary guidewire 10 is an example of an elongate medical device. The guidewire 10 includes an elongate shaft 12 extending from a distal region 14 to a proximal region 16. In some cases, as shown, the distal region 14 can include an atraumatic tip 18 disposed at a distal end 20 of the elongate shaft 12. The atraumatic tip 18 can be a separate element secured to the distal end 20 of the elongate shaft 12 via an adhesive if the atraumatic tip 18 is polymeric, or by welding if the atraumatic tip 18 is metallic. The atraumatic tip 18 can be formed, for example, as an integral part of the elongate shaft 12 or as an integral part of one of multiple components forming the elongate shaft 12.

[0023] In some cases, guidewire 10 may include a polymer layer 22, for example, to provide additional lubricity to guidewire 10. In some cases, polymer layer 22 may include a single polymer layer. Polymer layer 22 may include two or more different polymer layers, depending on the specific properties desired for guidewire 10. In some cases, for example, polymer layer 22 may include a first polymer, a first mixture of polymers, or a first blend of polymers in distal region 14, and polymer layer 22 may include a second polymer, a second mixture of polymers, or a second blend of polymers in proximal region 16. In some examples, guidewire 10 may not include a polymer layer 22.

[0024] FIG. 2 is a side view of guidewire 10 without polymer layer 22. Guidewire 10 may be viewed as including a coil segment 24, which may be considered to extend through distal region 14, and an elongated tubular member 26, which may be considered to extend through proximal region 16. In some examples, coil segment 24 may include both an inner coil and an outer coil, as shown in FIG. 3, for example. In some cases, elongated tubular member 26 may be an elongated polymer shaft having a single layer or multiple layers. In some cases, elongated tubular member 26 may be a hypotube. The hypotube may be, for example, metal, and in some cases, may be microfabricated to improve the flexibility of the hypotube without significantly affecting pushability and torque transmission.

[0025] FIG. 3 is a cross-sectional view of the guidewire 10 taken along line 3-3 of FIG. 2. As shown, the coil segment 24 includes an inner coil 28 and an outer coil 30. The inner coil 28 is formed from one or more filaments 32. The outer coil 30 is formed from one or more filers 34. In some cases, the inner coil 28 has a particular number of filers 32, such as one filer 32, two filers 32, three filers 32, or more filers, and the outer coil 30 has the same number of filers 34. In some cases, each of the one or more filers 32 forming the inner coil 28 has a filer diameter or filer wire size, and each of the one or more filers 34 forming the outer coil 30 has the same filer diameter or filer wire size. The inner coil 28 and the outer coil 30 have the same number of filers 32 and 34 (respectively), and each of these filers 32 and 34 is the same size wire. The inner coil 28 and the outer coil 30 are made of the same material.

[0026] The distal end 36 of the inner coil 28 and the distal end 38 of the outer coil 30 are secured to one another. As shown, the distal end 36 of the inner coil 28 and the distal end 38 of the outer coil 30 are secured together by a weld 40. The proximal end 42 of the inner coil 28 and the proximal end 44 of the outer coil 30 are secured to one another. As shown, the proximal end 42 of the inner coil 28 and the proximal end 44 of the outer coil 30 are welded together and joined to the distal end 46 of the elongated tubular member 26 via an annular weld 48.

[0027] Guidewire 10 includes a cable 50 extending through a lumen 52 formed by coil segments 24 and elongate tubular member 26. Cable 50 has a distal end 54 joined together with distal ends 36, 38 of inner coil 28, and outer coil 30 via welds 40. Cable 50 may be formed from a metallic material suitable for welding to distal ends 36, 38 of inner coil 28, and outer coil 30. Cable 50 is free to move within lumen 52, except for distal end 54, which is fixed.

[0028] The coil segment 24 of the guidewire 10 provides flexibility to the distal region 14 of the guidewire 10. In some cases, the inner coil 28 and the outer coil 30 each have a filer size ranging from 0.001 inch (0.0254 mm) to 0.005 inch (0.127 mm). The inner coil 28 and the outer coil 30 may each have a filer size ranging from 0.002 inch (0.0508 mm) to 0.004 inch (0.1016 mm), providing flexibility to the coil segment 24. As shown, the one or more filers 32 forming the inner coil 28 and the one or more filers 34 forming the outer coil 30 are closely packed, meaning that there is little space between adjacent filers. In some cases, small spaces may exist between adjacent filers 32, 34, respectively.

[0029] The coil segment 24 may have specific dimensions depending on the desired flexibility and other desired characteristics. The coil segment 24 may have an inner diameter (ID) ranging from 0.020 inches (0.508 mm) to 0.080 inches (2.032 mm). It will be understood that the ID of the coil segment 24 corresponds to the ID of the inner coil 28. The coil segment 24 may have an outer diameter (OD) ranging from 0.032 inches (0.8128 mm) to 0.0110 inches (0.2794 mm). It will be understood that the OD of the coil segment 24 corresponds to the OD of the outer coil 30. As used herein, the ID and OD of the coil segment 24 and the specific ID and OD of each of the inner coil 28 and outer coil 30 refer to the specific dimensions when the inner coil 28 and outer coil 30 are at rest and not under the influence of any external force that temporarily alters the configuration of the inner coil 28 and / or outer coil 30.

[0030] It will be appreciated that the outer diameter of the inner coil 28 needs to be equal to or less than the inner diameter of the outer coil 30 to allow the inner coil 28 to fit within the outer coil 30. In some cases, when assembling the guidewire 10, the inner coil 28 may be wound to temporarily reduce the diameter of the inner coil 28 to more easily fit the inner coil 28 within the outer coil 30. In some cases, the outer coil 30 may be unwound to temporarily increase the diameter of the outer coil 30 to more easily fit the inner coil 28 within the outer coil 30. In some instances, the relative difference between the outer diameter of the inner coil 28 and the inner diameter of the outer coil 30 is such that the inner coil 28 can extend within the outer coil 30 without requiring a temporary diameter change.

[0031] In some cases, the outer diameter of the inner coil 28 is selected to be the same as or substantially the same as the inner diameter of the outer coil 30. Here, substantially the same means that the inner diameter of the outer coil 30 is within about 5% of the outer diameter of the inner coil 28. In some cases, the inner diameter of the outer coil 30 is within about 1% of the outer diameter of the inner coil 28. The inner diameter of the outer coil 30 may be up to about 1 percent smaller, or up to about 5 percent smaller than the outer diameter of the inner coil 28.

[0032] In use, the coil segment 24 is very flexible. When the guidewire 10 encounters an obstruction or other difficult passage, tension can be applied to the cable 50, thereby stiffening the distal region 14 of the guidewire 10. Pulling the cable 50 relative to the rest of the guidewire 10 places the inner coil 28 and the outer coil 30 in compression. Because the inner coil 28 and the outer coil 30 are essentially the same except for the different winding directions (as described with respect to FIGS. 4 and 5), the inner coil 28 and the outer coil 30 exert equal force in both directions. This means that the inner coil 28 and the outer coil 30 can be compressed to increase their stiffness without being forced to bend or rotate in one direction or another.

[0033] Although not shown, it will be understood that guidewire 10 may include a proximal end that allows a user to apply tension to cable 50 by grasping and pulling on cable 50 when the user desires to increase the stiffness of distal region 14 of guidewire 10. This allows the user to, for example, push guidewire 10 through an obstacle. Once past the obstacle, the user can release cable 50, allowing distal region 14 of guidewire 10 to regain its original flexibility. In some cases, the user may be able to adjust the amount of increased stiffness of distal region 14 of guidewire 10 by applying a pulling force to cable 50.

[0034] FIG. 3 shows the inner coil 28 and outer coil 30 formed with filers 32 and 34, respectively, having a circular cross-sectional shape. In some cases, the inner coil 28 and outer coil 30 may be formed with filers having a more linear cross-sectional shape, such as a flat ribbon coil. FIG. 3A is a schematic cross-sectional view of the guidewire 10a. As shown, the coil segment 24a includes an inner coil 28a and an outer coil 30a. The inner coil 28a is formed from one or more filers 32a. The outer coil 30a is formed from one or more filers 34a. In some cases, the inner coil 28a has a particular number of filers 32a, such as one filer 32a, two filers 32a, three filers 32a, or more filers, and the outer coil 30a has the same number of filers 34a. In some cases, the one or more filers 32a forming the inner coil 28 each have a particular filer size, and the one or more filers 34a forming the outer coil 30a each have the same filer size. The inner coil 28a and the outer coil 30a have the same number of filers 32a and 34a (respectively), and each of these filers 32a and 34a is a ribbon of the same size. The inner coil 28a and the outer coil 30a are formed from the same material.

[0035] The distal end 36a of the inner coil 28a and the distal end 38a of the outer coil 30a are secured to one another. As shown, the distal end 36a of the inner coil 28a and the distal end 38a of the outer coil 30a are secured together by a weld 40a. The proximal end 42a of the inner coil 28a and the proximal end 44a of the outer coil 30a are secured to one another. As shown, the proximal end 42a of the inner coil 28a and the proximal end 44a of the outer coil 30a are welded together and joined to the distal end 46a of the elongated tubular member 26a via an annular weld 48a.

[0036] Guidewire 10a includes a cable 50a extending through a lumen 52a formed by coil segment 24a and elongate tubular member 26a. Cable 50a has a distal end 54a joined together with distal end 36a of inner coil 28a and distal end 38a of outer coil 30a via weld 40a. Cable 50a may be formed from a metallic material suitable for welding to distal end 36a of inner coil 28a and distal end 38a of outer coil 30a. Cable 50a is free to move within lumen 52a, except for distal end 54a, which is fixed.

[0037] The coil segment 24a of the guidewire 10a provides flexibility to the distal region 14a of the guidewire 10a. In some cases, the inner coil 28a and the outer coil 30a each have a filer dimension ranging from 0.001 inch (0.0254 mm) to 0.005 inch (0.127 mm). The inner coil 28a and the outer coil 30a each may have a filer dimension ranging from 0.002 inch (0.0508 mm) to 0.004 inch (0.1016 mm), providing flexibility to the coil segment 24a. In some cases, the inner coil 28a and the outer coil 30a may be formed from filers 32a and 34a, respectively, having a flat ribbon profile with a cross-sectional shape that is 0.001 inch (0.0254 mm) by 0.005 inch (0.127 mm), or 0.002 inch (0.0508 mm) by 0.004 inch (0.1016 mm), or perhaps 0.0015 inch (0.0381 mm) by 0.003 inch (0.0762 mm), or a combination thereof (such as 0.001 inch (0.0254 mm) by 0.004 inch (0.0381 mm), or perhaps 0.002 inch (0.0508 mm) by 0.005 inch (0.127 mm)). As shown, the one or more filers 32a forming the inner coil 28a and the one or more filers 34a forming the outer coil 30a are closely packed, meaning that there is little or no space between adjacent filers. In some cases, small gaps may exist between adjacent filers 32a, 34a, respectively.

[0038] The coil segment 24a may have specific dimensions depending on the desired flexibility and other desired characteristics. The coil segment 24a may have an inner diameter (ID) ranging from 0.020 inches (0.508 mm) to 0.080 inches (2.032 mm). It will be understood that the ID of the coil segment 24a corresponds to the ID of the inner coil 28a. The coil segment 24a may have an outer diameter (OD) ranging from 0.032 inches (0.8128 mm) to 0.0110 inches (0.2794 mm). It will be understood that the OD of the coil segment 24a corresponds to the OD of the outer coil 30a. As used herein, the ID and OD of the coil segment 24a and the specific ID and OD of each of the inner coil 28a and outer coil 30a refer to the specific dimensions when the inner coil 28a and outer coil 30a are at rest and not under the influence of any external force that temporarily alters the configuration of the inner coil 28a and / or outer coil 30a.

[0039] It will be appreciated that the outer diameter of the inner coil 28a needs to be equal to or less than the inner diameter of the outer coil 30a to allow the inner coil 28a to fit within the outer coil 30a. In some cases, when assembling the guidewire 10a, the inner coil 28a may be wound to temporarily reduce the diameter of the inner coil 28a to more easily fit the inner coil 28a within the outer coil 30a. In some cases, the outer coil 30a may be unwound to temporarily increase the diameter of the outer coil 30a to more easily fit the inner coil 28a within the outer coil 30a. In some instances, the relative difference between the outer diameter of the inner coil 28a and the inner diameter of the outer coil 30a is such that the inner coil 28a can extend within the outer coil 30a without requiring a temporary diameter change.

[0040] In some cases, the outer diameter of the inner coil 28a is selected to be the same as or substantially the same as the inner diameter of the outer coil 30a. Here, substantially the same means that the inner diameter of the outer coil 30a is within about 5% of the outer diameter of the inner coil 28a. In some cases, the inner diameter of the outer coil 30a is within about 1% of the outer diameter of the inner coil 28a. The inner diameter of the outer coil 30a may be up to about 1 percent smaller, or up to about 5 percent smaller, than the outer diameter of the inner coil 28a.

[0041] In use, the coil segment 24a is highly flexible. When the guidewire 10a encounters an obstruction or other difficult passage, tension can be applied to the cable 5a0 to stiffen the distal region 14a of the guidewire 10a. Pulling the cable 5a0 relative to the rest of the guidewire 10a places the inner coil 28a and the outer coil 30a in compression. Because the inner coil 28a and the outer coil 30a are essentially the same except for the different winding directions (as described with reference to FIGS. 4 and 5), the inner coil 28a and the outer coil 30a exert equal force in both directions. This means that the inner coil 28a and the outer coil 30a compress to increase stiffness without being forced to bend or rotate in one direction or another.

[0042] Figure 4 is a side view of a portion of the outer coil 30, and Figure 5 is a side view of a portion of the inner coil 28, showing that the outer coil 30 is wound in a first direction and the inner coil 28 is wound in an opposite second direction. Figure 4 shows that the one or more filers 34 forming the outer coil 30 are each wound in a first direction, with the filers 34 slanted from left to right and forming an angle α (alpha) with respect to a line 56 perpendicular to the longitudinal axis 58 of the outer coil 30. Figure 5 shows that the one or more filers 32 forming the inner coil 28 are each wound in a second direction, with the filers 32 slanted from right to left and forming an angle β (beta) with respect to a line 56 perpendicular to the longitudinal axis 58 of the inner coil 28.

[0043] As mentioned above, in some cases, the elongate tubular member 26 may be micromachined to enhance its flexibility. Accordingly, the elongate tubular member 26 may include various slots (not shown) cut into the elongate tubular member 26. The slots, if present, may be disposed at the same or similar angles relative to the longitudinal axis of the elongate tubular member 26. The slots may be disposed at a perpendicular or substantially perpendicular angle and / or may be characterized as being disposed in a plane perpendicular to the longitudinal axis. However, the slots may also be disposed at a non-perpendicular angle and / or may be characterized as being disposed in a plane that is not perpendicular to the longitudinal axis. In addition, one or more groups of slots may be disposed at a different angle relative to one or more other groups of slots. The slot arrangements and / or configurations may include, to the extent applicable, any of those disclosed in U.S. Patent Application Publication No. 2004 / 0181174, the entire disclosure of which is incorporated herein by reference.

[0044] The slots may be formed by methods such as micromachining, saw cutting (e.g., cutting with a semiconductor dicing blade embedded with diamond grit), electrical discharge machining, grinding, milling, casting, molding, chemical etching or processing, or other known methods. Some exemplary embodiments of suitable micromachining and other cutting methods, as well as structures for tubular members and medical devices including tubular members, are described in U.S. Patent Application Publication Nos. 2003 / 0069522 and 2004 / 0181174, and U.S. Patent Nos. 6,766,720 and 6,579,246, the entire disclosures of which are incorporated herein by reference. Some exemplary embodiments of etching processes are described in U.S. Patent No. 5,106,455, the entire disclosure of which is incorporated herein by reference.

[0045] In at least some embodiments, the slots can be formed in the tubular member using a laser cutting process. The laser cutting process can include a suitable laser and / or laser cutting device. For example, the laser cutting process can utilize a fiber laser. Utilizing a process such as laser cutting can be desirable for several reasons. For example, the laser cutting process can enable a variety of different cutting patterns in a precisely controlled manner. This can include variations in slot width, ring width, beam height and / or width, etc. Furthermore, changes in the cutting pattern can be made without having to change the cutting tool (e.g., blade).

[0046] The materials that can be used for the various components of guidewire 10 (and / or other guidewires disclosed herein) and the various tubular members disclosed herein may include components and materials commonly associated with medical devices. Guidewire 10 and / or other components of guidewire 10 may be made from metals, metal alloys, polymers (some examples of which are disclosed below), metal-polymer composites, ceramics, combinations thereof, etc., or other suitable materials. Examples of suitable metals and metal alloys include stainless steels, e.g., 304V, 304L, 316LV stainless steel, mild steel, nickel-titanium alloys such as linear elastic nitinol and superelastic nitinol, nickel-chromium-molybdenum alloys (e.g., UNS: N06625 such as INCONEL® 625, UNS: 06022 such as HASTELLOY® C-22®, UNS: N10276 such as HASTELLOY® C276®, and other HASTELLOY® alloys), nickel-copper alloys (e.g., UNS: N04400 such as MONEL® 400, NICKELVAC® 400, NICORROS® 400), nickel-cobalt-chromium-molybdenum alloys (e.g., MP35-N® UNS: R30035), nickel-molybdenum alloys (e.g., HASTELLOY® ALL ... B2®), other nickel-chromium alloys, other nickel-molybdenum alloys, other nickel-cobalt alloys, other nickel-iron alloys, other nickel-copper alloys, other nickel-tungsten alloys, or tungsten alloys; cobalt-chromium alloys; cobalt-chromium-molybdenum alloys (e.g., UNS:R30003, such as ELGILOY®, PHYNOX®); platinum-rich stainless steels; titanium; combinations thereof; or other suitable materials.

[0047] As suggested herein, the category referred to as "linear elastic" or "non-superelastic" includes a group of commercially available nickel-titanium or nickel alloys. These are chemically similar to conventional shape memory and superelastic materials, but exhibit different and useful mechanical properties. Linear elastic or non-superelastic Nitinol differs from superelastic Nitinol in that linear elastic or non-superelastic Nitinol does not exhibit a "superelastic plateau" or "flag region" in its stress / strain curve, as does superelastic Nitinol. Instead, linear elastic or non-superelastic Nitinol continues to increase in stress in a nearly linear or somewhat linear manner as recoverable strain increases, but this is not necessarily a linear relationship all the way to the point where the resin begins to deform, nor is it a more linear relationship than seen in the superelastic plateau or flag region seen in superelastic Nitinol. Therefore, for purposes of the present invention, linear elastic or non-superelastic Nitinol may be referred to as approximately linear elastic or non-superelastic Nitinol.

[0048] Linear elastic and non-superelastic Nitinol differ in that linear elastic and non-superelastic Nitinol can tolerate strains of approximately 2-5% while retaining elasticity (e.g., before plastically deforming), while superelastic Nitinol can tolerate strains of approximately 8% before plastically deforming. Both of these materials can be distinguished from other linear elastic materials, such as stainless steel (which can also be distinguished based on composition), which can only tolerate strains of approximately 0.2-0.44% before plastically deforming.

[0049] In some embodiments, linear elastic and / or non-superelastic nickel-titanium alloys are alloys that do not exhibit a martensite / austenite phase change detectable by differential scanning calorimetry (DSC) or dynamic metal thermal analysis (DMTA) over a wide temperature range. In some embodiments, linear elastic and / or non-superelastic nickel-titanium alloys do not exhibit a martensite / austenite phase change detectable by DSC or DMTA analysis over a temperature range from about -60°C to about 120°C. The mechanical flexural properties of these materials are inert to the effects of temperature over a very wide temperature range. In some embodiments, the mechanical flexural properties of linear elastic and / or non-superelastic nickel-titanium alloys at ambient or room temperature are approximately equivalent to the flexural properties at body temperature in that they do not exhibit a superelastic plateau or flag region. In other words, over a wide temperature range, linear elastic and / or non-superelastic nickel-titanium alloys maintain their linear elasticity or non-superelasticity.

[0050] In some embodiments, the linear elastic or non-superelastic nickel-titanium alloy is comprised of nickel in the range of about 50 to about 60 weight percent, with the remainder being primarily titanium. In some embodiments, the composition is nickel in the range of about 54 to about 57 weight percent. An example of a suitable nickel-titanium alloy is FHP-NT alloy, available from Furukawa Techno Material Co., Ltd., Kanagawa Prefecture, Japan. Examples of nickel-titanium alloys are disclosed in U.S. Patent Nos. 5,238,004 and 6,508,803, which are incorporated herein by reference. Other suitable materials include ULTANIUM®, available from Neo-Matrics, Inc., and GUM METAL®, available from Toyota Corporation. In other embodiments, a superelastic alloy, such as superelastic nitinol, is used to achieve the desired properties.

[0051] In at least some embodiments, a portion or all of guidewire 10 is doped with, formed of, or includes a radiopaque material. A radiopaque material is considered to be a material capable of forming a relatively bright image on a fluorescent screen or another imaging technique during a medical procedure. This relatively bright image allows a user of guidewire 10 to identify its location. Examples of radiopaque materials include, but are not limited to, gold, platinum, palladium, tantalum, tungsten alloys, polymeric materials with radiopaque fillers, and the like. Additionally, other radiopaque marker bands or coils may be incorporated into the design of guidewire 10 to achieve the same effect.

[0052] In some embodiments, magnetic resonance imaging (MRI) compatibility is added to guidewire 10. Portions of guidewire 10 are formed from materials that do not distort images and create artifacts (e.g., gaps in images). Certain ferromagnetic materials are unsuitable for MRI imaging because they create artifacts. Portions of guidewire 10 are also formed from materials that can be imaged by MRI machines. Materials that exhibit these properties include tungsten, cobalt-chromium-molybdenum alloys (e.g., UNS:R30003, such as ELGILOY® and PHYNOX®), nickel-cobalt-chromium-molybdenum alloys (e.g., UNS:R30035, such as MP35-N®), nitinol, and the like.

[0053] With respect to the elongate tubular member 26, the elongate tubular member 26 may be made from the same material along its length, or in some embodiments, may include portions or sections made from different materials. In some embodiments, the materials used may be selected to impart different flexibility and stiffness characteristics to different portions of the elongate tubular member 26. For example, the proximal and distal sections of the elongate tubular member 26 may be formed from different materials (e.g., materials having different moduli of elasticity) to create differences in flexibility.

[0054] In embodiments in which different portions of the elongate tubular member 26 are made from different materials, the different portions may be connected using suitable connection techniques and / or with connectors. For example, the different portions of the elongate tubular member 26 may be connected using welding (including laser welding), soldering, brazing, adhesives, etc., or combinations thereof. These techniques may be used regardless of whether or not connectors are utilized. The connector may include a structure generally suitable for connecting multiple portions of a guidewire. One example of a suitable structure includes a structure such as a hypotube or coiled wire having an inner diameter sized to receive and connect to the ends of the proximal and distal portions. Other suitable configurations and / or structures may be utilized for the connector 26, including the connectors described in U.S. Pat. Nos. 6,918,882 and 7,071,197, and / or U.S. Patent Application Publication No. 2006 / 0122537, the entire disclosures of which are incorporated herein by reference.

[0055] A sheath or cover (not shown) that forms a flat outer surface on guidewire 10 may be disposed over some or all of guidewire 10. However, in other embodiments, no such sheath or cover is present over a portion of guidewire 10, 110, and shaft 12, 112 forms the outer surface. The sheath may be formed of a polymer or other suitable material. Suitable polymeric materials include polytetrafluoroethylene (PTFE), tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), polyoxymethylene (POM, e.g., DELRIN® available from DuPont), polyether block esters, polyurethanes (e.g., polyurethane 85A), polypropylene (PP), polyvinyl chloride (PVC), polyetheresters (e.g., ARNITEL® available from DSM Engineering Plastics), ether or ether-based copolymers (e.g., butylene / poly(alkylene ether) phthalates and polyester elastomers such as HYRTREL® available from DuPont), polyamides (e.g., DURETHAN® available from Bayer, or CRISTAMID® available from ElfAtochem), elastomeric polyamides, block polyamide / ethers, polyether block amides (e.g., PEBA available under the trademark PEBAX®), ethylene vinyl acetate copolymers (EVA), silicone, polyethylene (PE), Marlex high density polyethylene, Marlex low density polyethylene, linear low density polyethylene (e.g., REXELL®), polyester, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polytrimethylene terephthalate, polyethylene naphthalate (PEN), polyether ether ketone (PEEK), polyimide (PI).Examples of suitable materials include polyetherimide (PEI), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polyphenylene terephthalamide (e.g., KEVLAR®), polysulfone, nylon, nylon-12 (e.g., GRILAMID® available from EMS American Grilon), perfluoro(propyl vinyl ether) (PFA), ethylene vinyl alcohol, polyolefin, polystyrene, epoxy, polyvinylidene chloride (PVdC), poly(styrene-b-isobutylene-b-styrene) (e.g., SIBS and SIBS 50A), polycarbonate, ionomers, biocompatible polymers, and other suitable materials, as well as blends, combinations, copolymers, polymer / metal composites, and the like. In some embodiments, the sheath is blended with a liquid crystal polymer (LCP). The blend can contain up to about 6% LCP.

[0056] In some embodiments, the outer surface of the guidewire is sandblasted, bead-blasted, sodium bicarbonate-blasted, or electropolished. In these and other embodiments, a coating, such as a lubricious, hydrophilic, protective, or other coating, is applied to part or all of the sheath, or to other portions of the guidewire 10 in sheath-less embodiments. Alternatively, the sheath may include a lubricious, hydrophilic, protective, or other type of coating. A hydrophobic coating, such as a fluoropolymer, may provide dry lubricity to improve guidewire steerability and device exchange. A lubricious coating may improve steerability and wound crossing. Suitable lubricious polymers are known in the art and include hydrophilic polymers such as silicones and the like, high-density polyethylene (HDPE), polytetrafluoroethylene (PTFE), polyarylene oxides, polyvinylpyrrolidone, polyvinyl alcohol, hydroxy alkyl celluloses, algins, saccharides, and caprolactone. The hydrophilic polymer may be mixed with a hydrophilic polymer or with a certain amount of water-insoluble components (including some polymers) to form a coating with suitable lubricity, binding, and solubility properties. Further examples of such coatings, materials, and methods of forming coatings are disclosed in U.S. Patent Nos. 6,139,510 and 5,772,609, which are incorporated herein by reference.

[0057] The coating and / or sheath may be formed by covering, extruding, co-extruding, interupted layer co-extrusion (ILC), or fusing several sections end-to-end. The same can be true for the atraumatic tip 18. The layers may be uniform or have a gradually decreasing stiffness from the proximal to the distal end. The gradually decreasing stiffness layer may be continuous if formed by ILC, or graduated if formed by fusing individually extruding tubular sections. The outer layer may contain a radiopaque filler to facilitate visualization with radiation. Those skilled in the art will recognize that such materials may vary without departing from the scope of this disclosure.

[0058] It should be understood that in many respects, this disclosure is merely illustrative. Changes may be made in details, particularly in matters of shape, size, and arrangement of steps, without departing from the scope of the present invention. This includes, to the extent appropriate, substituting elements of one illustrative embodiment for other embodiments. The scope of the present invention is, of course, defined by the language expressed in the appended claims.

Claims

1. 1. An elongate medical device, comprising: a distal segment adapted to provide adjustable flexibility, an inner coil having one or more inner coil filers extending in a first direction at an inner coil angle; an outer coil having one or more outer coil filers extending in a second direction opposite the first direction at an outer coil angle, wherein the inner coil angle is equal to the outer coil angle; the distal segment including a cable extending through the inner coil and extending proximally from the inner coil, the distal end of the cable being welded together with the distal end of the inner coil and the distal end of the outer coil; a proximal segment defining an elongate shaft, the distal end of the elongate shaft being welded to the proximal end of the inner coil and the proximal end of the outer coil; The elongate medical device, wherein the distal segment is configured to increase in stiffness when a tensile force is applied to the cable.

2. The elongate medical device of claim 1 , wherein the inner coil has an outer diameter and the outer coil has an inner diameter equal to the outer diameter of the inner coil.

3. 3. The elongate medical device of claim 1 or 2, wherein the inner coil has multiple filers and the outer coil has the same number of filers.

4. 3. The elongated medical device of claim 1, wherein each of the one or more inner coil filers has a wire diameter and each of the one or more outer coil filers has the same wire diameter.

5. The elongate medical device of claim 1 or 2, wherein the elongate shaft comprises a hypotube.

6. The elongate medical device of claim 1 or 2, wherein a proximal end of the inner coil and a proximal end of the outer coil are fixed to a distal end of the elongate shaft.

7. The elongate medical device of claim 1 or 2, wherein the cable extends through the elongate shaft.

8. 3. The elongate medical device of claim 1 or 2, wherein the distal end of the cable, the distal end of the inner coil, and the distal end of the outer coil are all fixed together at the distal end of the elongate medical device.

9. 6. The elongate medical device of claim 5, wherein the proximal end of the inner coil and the proximal end of the outer coil are welded together and to the distal end of the hypotube.

10. 3. The elongate medical device of claim 1 or 2, wherein the distal end of the inner coil, the distal end of the outer coil, and the distal end of the cable are all welded together.

11. 3. The elongate medical device of claim 1 or 2, wherein applying tension to the cable relative to the elongate shaft increases the stiffness of the inner coil and outer coil combination.

12. 3. The elongate medical device of claim 2, wherein the inner diameter of the outer coil is at most 1% smaller or at most 5% smaller than the outer diameter of the inner coil.

13. A guidewire, a coil assembly including an inner coil having one or more inner coil filers extending in a first direction and an outer coil having one or more outer coil filers extending in a second direction, the inner coil having an outer diameter and the outer coil having an inner diameter, the inner diameter of the outer coil being within 5% of the outer diameter of the inner coil; a cable having an attachment point coupled together with a distal end of the inner coil and a distal end of the outer coil, the cable extending freely in a proximal direction from the attachment point; The cable is configured to provide a compressive force to the coil assembly, thereby temporarily increasing the stiffness of the coil assembly.

14. 14. The guidewire of claim 13, wherein the one or more inner coil filers extend at a coil angle and the one or more outer coil filers extend at the same coil angle.

15. the inner coil has a number of filers and the outer coil has the same number of filers; 15. The guidewire of claim 13 or 14, wherein each of the one or more inner coil filers has a wire diameter and each of the one or more outer coil filers has the same wire diameter.

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