Guide wire

A guide wire includes a core shaft, a coil body disposed around an outer periphery of the core shaft, and a joining portion joining a distal end of the core shaft to a distal end of the coil body 3. An outer periphery of the joining portion has, at its proximal end, an uneven shape in a longitudinal direction of the guide wire. The outer periphery may include a protruded portion that protrudes proximally in the longitudinal direction, and a recessed portion that protrudes distally in the longitudinal direction. The guide wire has improved joining strength between the joining portion and the coil body, preventing the joining portion from detaching from the coil body.

BACKGROUND

The disclosed embodiments relate to a medical device. Specifically, the disclosed embodiments relate to a guide wire used as a guide for inserting a catheter into a lumen in the body such as a blood vessel or a ureter, and for inserting an indwelling device into a site of an aneurysm formed in a blood vessel.

A guide wire used as a guide for inserting a catheter into a lumen in the body and for inserting an indwelling device into a site of an aneurysm formed in a blood vessel generally comprises a core shaft, a coil body covering a distal end part of the core shaft, a distal end joining portion joining a distal end of the core shaft to a distal end of the coil body, and a proximal end joining portion joining the core shaft to a proximal end of the coil body.

For example, US 2007/0185415 describes a guide wire comprising a core wire (hereafter referred to as a core shaft), a coil body covering a distal end part of the core shaft, and a proximal end joining portion joining a distal end of the core shaft to a proximal end of the coil body. A distal end joining portion is joined to a distal end of the coil body (see, for example, FIG. 12A and FIG. 12B of US 2007/0185415).

In order to insert a catheter into a patient's body, for example, an operator inserts the guide wire described in US 2007/0185415 into the patient's body so that it advances toward a narrowed segment or the like in the patient's body, and then penetrates the narrowed segment. However, the guide wire may become stuck at the narrowed segment when the operator tries to penetrate the narrowed segment with the guide wire. If that happens, the operator will try to push, pull, or rotate a connector fixed at a proximal end part of the guide wire to release the guide wire from the narrowed segment.

However, in the case of a conventional guide wire, the distal end joining portion of the guide wire may detach from the coil body when the operator tries to push, pull, or rotate the stuck guide wire. If the distal end joining portion detaches from the coil body, the detached distal end joining portion may be left in the patient's body, complicating any subsequent treatment.

SUMMARY

The disclosed embodiments have been devised in order to address the above problem. An object of the disclosed embodiments is to provide a guide wire in which the joining strength between a distal end joining portion of the guide wire and a coil body is improved, preventing the distal end joining portion from detaching from the coil body.

In order to achieve the above object, a guide wire of the disclosed embodiments comprises a core shaft, a coil body covering an outer periphery of the core shaft, and a joining portion joining a distal end of the core shaft to a distal end of the coil body. An outer periphery of the joining portion has at its proximal end an uneven shape in the longitudinal direction of the guide wire. Therefore, the joining strength between the joining portion and the coil body is improved, preventing the joining portion from detaching from the coil body.

The guide wire may include a protruded portion that protrudes proximally in the longitudinal direction and a recessed portion beyond which the protruded portion extends proximally. The recessed portion may be formed in a curved fashion, which prevents stress from concentrating at the joining portion when the guide wire is bent. This in turn prevents the joining portion from detaching from the coil body.

The coil body may be formed by spirally winding two or more twisted wires, each twisted wire having multiple element wires twisted together. The guide wire can therefore be formed in a simpler manner.

DETAILED DESCRIPTION OF EMBODIMENTS

Below, the embodiments will be described with reference to the drawings.

FIG. 1shows an overall view of a guide wire according to the disclosed embodiments.FIG. 2shows an enlarged view of a distal end of the guide wire shown inFIG. 1.FIG. 3shows a longitudinal cross-sectional view of the distal end of the guide wire shown inFIG. 2. Throughout this disclosure, descriptions will be omitted for the parts already described, to which the same reference numbers will be assigned in the figures.

With reference toFIG. 1, a guide wire1comprises a core shaft5, a coil body3covering (disposed around) a distal end part of the core shaft5, a distal end joining portion7joining a distal end of the coil body3to a distal end of the core shaft5, and a proximal end joining portion6joining a proximal end of the coil body3to the core shaft5.

The core shaft5is a rod having a round cross section. The core shaft5is tapered from its proximal end toward its distal end. There is no particular limitation for the material of the core shaft5, but stainless steel is used for purposes of this discussion. Superelastic alloys such as Ni—Ti alloy may also be used.

The coil body3, which has a hollow cylindrical shape, is spirally wound around the core shaft5. There is also no particular limitation for the material of the coil body3, but stainless steel is used for purposes of this discussion. Tungsten may also be used.

Note that the coil body3is formed by winding one metal element wire at a relatively large twist angle with respect to the longitudinal direction of the guide wire1.

The distal end joining portion7, which has an approximately hemispherical shape, constitutes the distal end of the guide wire1, and an outer diameter of a proximal end of the distal end joining portion7is approximately the same as an outer diameter of the coil body3. There is no particular limitation for the material of the distal end joining portion7, but an Ag—Sn-based solder material is used for purposes of this discussion. An Au—Sn-based solder material may also be used.

Further, the distal end joining portion7has a rectangular protruded portion8that protrudes proximally in the longitudinal direction of the guide wire1, and a rectangular recessed portion9that extends distally in the longitudinal direction. That is, as seen in a cross section (which corresponds to the “cross-sectional view” described herein) of the distal end joining portion7cut in a direction perpendicular to the plane of the sheet ofFIG. 2(cut in a direction perpendicular to the longitudinal direction of the guide wire1), the length of the distal end joining portion7in the longitudinal direction differs along an outer periphery of the distal end joining portion7, and the rectangular protruded portion8and the rectangular recessed portion9form an uneven shape in the longitudinal direction.

An outer diameter of the proximal end joining portion6is approximately the same as the outer diameter of the coil body3. There is no particular limitation for the material of the proximal end joining portion6, but an Ag—Sn-based solder material is used for purposes of this discussion. An Au—Sn-based solder material may also be used.

In the guide wire1, the proximal end of the distal end joining portion7is formed into an uneven shape in the longitudinal direction along the outer periphery of the distal end joining portion7, and thus a distortion of the coil body3upon bending the guide wire1can be reduced by means of a space2defined by the rectangular protruded portion8and the rectangular recessed portion9. As a result, the joining strength between the distal end joining portion7and the coil body3of the guide wire1can be improved, preventing the distal end joining portion7from detaching from the coil body3.

Note that inFIG. 2, the rectangular protruded portion8does not extend along a length of the element wire of the coil body3. However, the length of the protruded portion8can be altered so that the protruded portion8extends along a length of the element wire of the coil body3in order to further improve the joining strength between the distal end joining portion7and the coil body3.

Further, distortion of the coil body3upon bending the guide wire1can also be reduced by means of a space4(gap) defined by the rectangular protruded portion8and the core shaft5as shown inFIG. 3. As a result, the joining strength between the distal end joining portion7and the coil body3can be improved, preventing the distal end joining portion7from detaching from the coil body3.

With reference toFIG. 4, a guide wire11comprises the core shaft5, a coil body13covering the distal end part of the core shaft5, and a distal end joining portion17joining a distal end of the coil body13to the distal end of the core shaft5.FIG. 5shows a longitudinal cross-sectional view of a distal end of the guide wire11.

The coil body13, which has a hollow cylindrical shape, is spirally wound around the core shaft5. There is no particular limitation for the material of the coil body13, but stainless steel is used for purposes of this discussion. Tungsten may also be used.

Note that the coil body13is formed by twisting multiple metal element wires (10 metal element wires as shown inFIG. 5) into a hollow cylindrical shape such that the twist angle with respect to the longitudinal direction of the guide wire11is relatively small.

The distal end joining portion17, which has an approximately hemispherical shape, constitutes the distal end of the guide wire11. There is no particular limitation for the material of the distal end joining portion17, but an Au—Sn-based solder material is used for purposes of this discussion. An Au—Sn-based solder material may also be used.

Further, the distal end joining portion17has a rectangular protruded portion18that protrudes proximally in the longitudinal direction of the guide wire11, and a curved recessed portion19that extends distally in the longitudinal direction. That is, as seen in the “cross-sectional view,” the length of the distal end joining portion17in the longitudinal direction differs along an outer periphery of the distal end joining portion17, and the rectangular protruded portion18and the curved recessed portion19form an uneven shape in the longitudinal direction.

In the guide wire11, a proximal end of the distal end joining portion17is formed into an uneven shape in the longitudinal direction along the outer periphery of the distal end joining portion17, and thus a distortion of the coil body13upon bending the guide wire11can be reduced by means of a space12defined by the rectangular protruded portion18and the curved recessed portion19. In addition, stress is prevented from concentrating at the distal end joining portion17when the guide wire11is bent, further preventing detachment of the distal end joining portion17from the coil body13.

Further, distortion of the coil body13upon bending the guide wire11can also be reduced by means of a space14(gap) defined by the rectangular protruded portion18and the core shaft5. As a result, the joining strength between the distal end joining portion17and the coil body13can be improved, preventing the distal end joining portion17from detaching from the coil body13.

With reference toFIG. 6, a guide wire21comprises the core shaft5, a coil body23covering the distal end part of the core shaft5, and a distal end joining portion27joining a distal end of the coil body23to the distal end of the core shaft5.FIG. 7shows a longitudinal cross-sectional view of a distal end of the guide wire21.

The coil body23, which has a hollow cylindrical shape, is spirally wound around the core shaft5. There is no particular limitation for the material of the coil body23, but stainless steel is used for purposes of this discussion. Tungsten may also be used.

Note that the coil body23is formed by spirally winding10twisted wires25around the core shaft5, the twisted wires25each being formed by twisting together 7 metal element wires (seeFIG. 7).

The distal end joining portion27, which has an approximately hemispherical shape, constitutes the distal end of the guide wire21. There is no particular limitation for the material of the distal end joining portion27, but an Ag—Sn-based solder material is used for purposes of this discussion. An Au—Sn-based solder material may also be used.

Further, the distal end joining portion27has a wedge-shaped protruded portion28that protrudes proximally in the longitudinal direction of the guide wire21, and a rectangular recessed portion29that extends distally in the longitudinal direction. That is, as seen in the “cross-sectional view,” the length of the distal end joining portion27in the longitudinal direction differs along an outer periphery of the distal end joining portion27, and the wedge-shaped protruded portion28and the rectangular recessed portion29form an uneven shape in the longitudinal direction.

In the guide wire21, a proximal end of the distal end joining portion27is formed into an uneven shape in the longitudinal direction along the outer periphery of the distal end joining portion27, and thus a distortion of the coil body23upon bending the guide wire21can be reduced by means of a space22defined by the wedge-shaped protruded portion28and the rectangular recessed portion29. In addition, a solder material constituting the distal end joining portion27is allowed to permeate between the metal element wires of the twisted wires25to improve the joining strength between the distal end joining portion27and the coil body23of the guide wire21. This can further prevent detachment of the distal end joining portion27from the coil body23.

Further, distortion of the coil body23upon bending the guide wire21can also be reduced by means of a space24(gap) defined by the wedge-shaped protruded portion28and the core shaft5as shown inFIG. 7. As a result, the joining strength between the distal end joining portion27and the coil body23can be improved, preventing the distal end joining portion27from detaching from the coil body23.

With reference toFIG. 8, a guide wire31comprises the core shaft5, a coil body33covering the distal end part of the core shaft5, a distal end joining portion37joining a distal end of the coil body33to the distal end of the core shaft5, and a proximal end joining portion36joining a proximal end of the coil body33to the core shaft5.FIG. 9shows an enlarged view of a distal end of the guide wire31. Note that a longitudinal cross-sectional view is omitted because it is the same asFIG. 7.

The coil body33, which has a hollow cylindrical shape, is spirally wound around the core shaft5. There is no particular limitation for the material of the coil body33, but stainless steel is used for purposes of this discussion. Tungsten may also be used.

Note that the coil body33is formed by spirally winding10twisted wires35around the core shaft5, the twisted wires35each being formed by twisting 7 Metal element wires as in the coil body23.

The distal end joining portion37, which is of an approximately hemispherical shape, constitutes the distal end of the guide wire31. There is no particular limitation for the material of the distal end joining portion37, but an Ag—Sn-based solder material is used for purposes of this discussion. An Au—Sn-based solder material may also be used.

Further, the distal end joining portion37has a wedge-like protruded portion38that protrudes proximally in the longitudinal direction of the guide wire31, and a curved recessed portion39that extends distally in the longitudinal direction. That is, as seen in the “cross-sectional view,” the length of the distal end joining portion37in the longitudinal direction differs along an outer periphery of the distal end joining portion37, and the wedge-shaped protruded portion38and the curved recessed portion39form an uneven shape in the longitudinal direction.

An outer diameter of the proximal end joining portion36at the distal end part is approximately the same as an outer diameter of the coil body33. There is no particular limitation for the material of the distal end joining portion36, but an Ag—Sn-based solder material is used for purposes of this discussion. An Au—Sn-based solder material may also be used.

In the guide wire31, a proximal end of the distal end joining portion37is formed into an uneven shape in the longitudinal direction along the outer periphery of the distal end joining portion37, and thus a distortion of the coil body33upon bending the guide wire31can be reduced by means of a space32defined by the wedge-shaped protruded portion38and the curved recessed portion39.

Further, a solder material constituting the distal end joining portion37is allowed to permeate between the metal element wires of the twisted wires35to further improve the joining strength between the distal end joining portion37and the coil body33of the guide wire31. Stress is prevented from concentrating at the distal end joining portion37when the guide wire11is bent, which in turn prevents the distal end joining portion37from detaching from the coil body33.

The present invention shall not be limited to the embodiments described above. The present invention may be practiced with various modifications made without departing from the scope of the present invention.

For example, the coil bodies of the guide wires according to the above embodiments are formed with metal element wires, but they may be formed with one or more resin element wires. However, a coil body formed with one or more metal element wires may be convenient when the distal end joining portion comprises a solder material.

Further, the distal end joining portions in the aforementioned embodiments are made of an Ag—Sn-based solder material or an Au—Sn-based solder material, but a core shaft may be also fixed to a coil body with an adhesive. However, an Ag—Sn-based solder material or an Au—Sn-based solder material can provide a better bonding strength based on previous experiences.