JP6653187B2 - Medical guidewire - Google Patents

Description

  The present invention relates to a medical guidewire. In particular, the invention relates to medical guidewires used in imaging devices.

  An OCT (Optical Coherence Tomography: Optical Coherence Tomography) method is known as a technique for performing tomography in a living body lumen such as a blood vessel using a catheter (see Patent Document 1). A catheter used in the OCT method has a tubular guide wire holding portion through which a guide wire is inserted, at a distal end thereof. In addition, a shaft having a light irradiator that emits light such as infrared light from the distal end is inserted into the lumen formed in the catheter. While the guide wire is inserted through the guide wire holding unit, the shaft is rotated around the axis of the catheter, and the light emitted from the light irradiation unit is received while moving in the proximal direction of the catheter, so that the blood vessel Tomography of a wall or the like is performed.

JP 2005-95624 A

  In the conventional OCT method using a catheter and a guide wire, since the guide wire extends along the outside of the catheter, as shown in FIG. 1, infrared rays emitted from the light irradiation unit are blocked by the guide wire. Is inevitable, and the shadow caused by the guide wire is generated. For this reason, tomography of a blood vessel wall or the like becomes impossible in a portion where a shadow occurs, and there is a problem that a diagnosis of this portion may be hindered.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a technique that makes it difficult to generate a shadow of a guide wire when performing tomography in a living body lumen such as a blood vessel using an imaging catheter. .

The medical guidewire of the present invention, in a state where the medical guidewire is separately arranged on the outer peripheral side of the imaging catheter in the body lumen, separately from the medical guidewire in the lumen of the imaging catheter. It is used at the time of tomography in the living body lumen , which is performed by receiving infrared light emitted from the arranged light irradiation unit , and has a flexible core portion and a distant portion of the core portion. A first coil portion in which a first wire having radiopaque properties is spirally wound at a position end portion, and a second wire is spirally wound around the core portion proximal to the first coil portion. a second coil portion wound on Jo, while covering the second coil portion, a resin layer having an infrared transparent which transmits the infrared irradiated from the light irradiation unit during the tomography, It is provided with. The wire diameter of the second strand is smaller than the wire diameter of the first strand, and the gap between the second strands is larger than the gap between the first strands. The second wire in the core and the second coil portion, and with that in a partially shielding the infrared rays irradiated from the light irradiation unit during the tomography, the second coil portion the gap between the second wire in the infrared irradiated from the light irradiation unit during the tomography, and transmit without being interrupted.

  In the medical guidewire according to the aspect described above, a gap between the second wires in the second coil portion may be equal to or greater than 2.1 times an outer diameter of the second wires. The outer diameter of the core may be 250 μm or less. The resin layer may be formed of a UV curable resin.

  A combination of the above-described elements as appropriate may be included in the scope of the invention for which protection is sought by the present patent application.

  ADVANTAGE OF THE INVENTION According to this invention, when performing tomographic imaging of a living body lumen such as a blood vessel using an imaging catheter, a shadow of a guide wire can be made less likely to occur.

It is a figure for explaining a shadow of a guide wire which occurs at the time of tomography. It is a top view showing the outline of the medical guide wire concerning an embodiment. It is sectional drawing in the cut surface along the axial direction of the medical guidewire which concerns on embodiment. It is a top view which shows the winding state of the strand of the connection part of the 1st coil and 2nd coil of the medical guidewire which concerns on embodiment. It is the schematic for demonstrating a shadowing index.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment)
FIG. 2 is a plan view schematically showing the medical guidewire 10 according to the embodiment. FIG. 3 is a cross-sectional view of a cut surface along the axial direction of the medical guidewire 10. The medical guidewire 10 is used together with an imaging catheter (hereinafter, referred to as an OCT catheter) used for the OCT method. The medical guidewire 10 has a core part 20, a first coil part 30, a second coil part 40, and a coating layer 50 as main components.

  As shown in FIG. 3, the core portion 20 is located on the proximal side of the medical guidewire 10, and has a region R <b> 1 having a substantially constant outer diameter along the axial direction and a distal side of the medical guidewire 10. A region R2 which is located and has a substantially constant outer diameter along the axial direction, and a tapered region R3 which is located between the region R1 and the region R2 and whose outer diameter gradually decreases in the distal direction. ing.

  The outer diameter of the core portion 20 in the region R1 is preferably equal to or less than 250 μm, and more preferably equal to or less than 190 μm. Further, the outer diameter of the core portion 20 in the region R2 is preferably 150 μm or less, and more preferably 100 μm or less.

  The core 20 is formed of a material that exhibits flexibility as a core material of a medical guidewire, and examples thereof include a superelastic alloy such as a Ni—Ti alloy and a metal such as stainless steel.

  The first coil portion 30 is formed by spirally winding a first element wire in a region on the distal side of the core portion 20, in the present embodiment, in a region R2 of the core portion 20. In the first coil section 30, it is preferable that the first element wire is densely wound without any gap. Thereby, the X-ray opacity in the first coil unit 30 can be increased.

  Examples of the material of the first strand include a metal having radiopaque properties, for example, platinum, palladium, rhenium, and alloys thereof. By forming the first coil portion 30 from a material having radiopaque properties, the position of the distal end portion of the medical guidewire 10 can be confirmed under fluoroscopy.

  The outer diameter of the first strand is preferably 50 μm or more and 70 μm or less. The length of the first coil portion in the axial direction of the medical guidewire 10 is preferably 10 mm or more. According to this, sufficient X-ray opacity can be ensured in the first coil unit 30.

  The distal end of the first coil section 30 is fixed to the distal end of the core section 20 by a joining member 60 such as solder.

  The second coil section 40 is formed by spirally winding a second element wire around the core section 20 closer to the first coil section 30. The flexibility and flexibility of the medical guidewire 10 can be improved by the second coil portion 40.

  Examples of the material of the second strand include a metal such as stainless steel. The wire diameter of the second strand is smaller than the wire diameter of the first strand. Further, the gap between the second strands is larger than the gap between the first strands.

  The outer diameter of the second strand is preferably 30 μm or more and 60 μm or less from the viewpoint of sufficient flexibility and flexibility. The gap between the second strands is preferably 2.1 to 6 times the outer diameter of the second strands. By setting the gap between the second wires to be at least 2.1 times the outer diameter of the second wires, the size of a portion that shields infrared rays during tomography in a living body lumen such as a blood vessel is reduced, and a guide wire is provided. Shadows are less likely to occur. On the other hand, if the gap between the second strands is larger than six times the outer diameter of the second strand, it becomes difficult to form the covering portion 50 by a method described later.

  A portion on the proximal side of the first coil portion 30 and a portion on the distal side of the second coil portion 40 are joined by a joining member 62 such as solder. More specifically, as shown in FIG. 4, a first wire at a proximal end portion of the first coil portion 30 and a second wire at a distal end portion of the second coil portion 40 have a gap therebetween. And wound around the core portion 20, and the joining member 62 covers an area where the first strands and the second strands are alternately wound.

  The proximal end of the second coil 40 is fixed to the proximal end of the core 20 by a joining member 64 such as solder.

  The covering section 50 covers the second coil section 40. The covering portion 50 is formed of a resin having infrared transmittance. Here, “infrared transmittance” means that the infrared transmittance in the near infrared region is 10% or more. Examples of the resin include UV curable resins such as urethane acrylate, epoxy acrylate, silicone acrylate, acrylic acrylate, and polyester acrylate. The covering portion 50 can maintain the position of the second coil portion 40 and can enhance the kink resistance of the medical guidewire 10 in a region where the second coil portion 40 exists. In addition, the insertability of the OCT catheter used in combination with the medical guidewire 10 can be improved by the covering portion 50. In addition, by applying a coating having lubricity to the surface of the covering portion 50, the blood vessel can be further prevented from being damaged.

  As a manufacturing method of the covering portion 50, a resin before curing is prepared, and the core portion 20 and the second coil portion 40 are immersed (dipped) in the melting, and then irradiated with UV to cure the resin. There is a method to make it. When the gap between the second strands is larger than six times the outer diameter of the second strand, when the core 20 and the second coil section 40 are dipped in the resin before curing, the gap between the second strands is reduced. And it becomes difficult to adhere enough resin, and the coating portion 50 after curing becomes mottled. In addition, by setting the gap between the second strands to be less than six times the outer diameter of the second strand, the fixation of the covering portion 50 to the core portion 20 and the second coil portion 40 is improved, and the medical guide wire 10 Can be improved in reliability.

  Since the covering portion 50 has infrared transmittance, the core portion 20 and the second coil portion 40 are portions that shield infrared rays, and the outer diameter of the portion that shields infrared rays when viewed from the light irradiation unit for tomography is the fourth portion. It is smaller than the physical outer diameter of the medical guidewire 10 in the region where the two coil portions 40 exist. As described above, the wire diameter of the second wire of the second coil part 40 is smaller than the wire diameter of the first wire, and the gap between the second wires is the gap between the first wires. It is getting bigger. For this reason, the degree of shielding of the infrared rays of the second coil portion 40 is greatly reduced, and the outer diameter of the portion that shields the infrared rays is closer to the outer diameter of the core portion 20 as viewed from the light irradiation section for tomography. . The degree of shielding of the second coil portion 40 from infrared rays is reduced as the wire diameter of the second strand is smaller, the gap between the second strands is larger, and the outer diameter of the core 20 is smaller.

  The medical guidewire 10 described above has an outer diameter of a portion that shields infrared rays when viewed from a tomographic light irradiator, and has an outer diameter physically outside the medical guidewire 10 in a region where the second coil portion 40 exists. Since the diameter is smaller than the diameter and close to the outer diameter of the core portion 20, the shadow of the medical guidewire 10 can be made less likely to occur at the time of tomography of a living body lumen such as a blood vessel. Note that, in the medical guidewire 10 of the present embodiment, the outer diameter of the core portion 20 is 250 μm or less, preferably 190 μm or less, and is set to be narrower than a conventional medical guidewire. Thereby, the shadow of the medical guidewire 10 is more unlikely to occur. In addition, it is possible to make it difficult for the medical guidewire 10 to be bent during operation, and to ensure the visibility of the first coil unit 30 under X-ray fluoroscopy.

  Hereinafter, examples of the present invention will be described. However, these examples are merely examples for suitably describing the present invention, and do not limit the present invention in any way.

(Example)
The outer diameter of the core 20 in the region R1 is 180 μm, the outer diameter of the core 20 in the region R2 is 80 μm, the outer diameter of the first wire in the first coil 30 is 60 μm, and the length of the first coil is 20 mm. A medical guidewire was manufactured by setting the outer diameter of the second wire in the second coil portion 40 to 40 μm, the gap between the second wires to be four times the outer diameter of the second wire, and the resin of the covering portion 50 to be urethane acrylate. .

(Comparative example)
The outer diameter of the core portion 20 in the region R1 is 260 μm, the outer diameter of the core portion 20 in the region R2 is 105 μm, the outer diameter of the first wire in the first coil portion 30 is 60 μm, and the length of the first coil portion is 30 mm. The outer diameter of the second strand in the second coil part 40 is 50 μm, the gap between the second strands is 0.1 times the outer diameter of the second strand, and the sheath 50 is covered with a medical guide wire that is not coated with resin. Produced.

In both the examples and comparative examples, OCT images were measured at a position 150 mm from the tip of the medical guidewire. From the obtained OCT image, L and Measured angle θ were measured as shown in FIG. 5, and from the three parameters of the physical outer diameter R of the medical guide wire, which was a design value measured in advance, the following equation was obtained. The Shading index defined by was calculated.
Shading index = 0.039 (2L + R) sin (Measured angle θ / 2)
The shadowing index is equivalent to a virtual outer diameter of the medical guidewire that causes a shadow, and under the same conditions, the smaller the value of the shadowing index, the less the shadow by the medical guidewire is generated.

  Table 1 shows the obtained results. As shown in Table 1, it was confirmed that the shadowing index of the medical guidewire of the example was significantly reduced and the shadow of the medical guidewire was less likely to be generated than that of the medical guidewire of the comparative example.

  The present invention is not limited to the above-described embodiments, and various modifications such as design changes can be made based on the knowledge of those skilled in the art. Embodiments can also be included in the scope of the present invention.

  For example, in the embodiment described above, the outer diameter in the region R2 is substantially constant, but may be formed in a tapered shape so as to be tapered.

DESCRIPTION OF SYMBOLS 10 Medical guide wire, 20 core part, 30 1st coil part, 40 2nd coil part, 50 covering part, 60 joining members, 62 joining members, 64 joining members

Claims (4)

In a state where the medical guidewire is separately arranged on the outer peripheral side of the imaging catheter in the living body lumen, the light is irradiated from the light irradiation unit separately arranged from the medical guidewire into the lumen of the imaging catheter. performed by receiving infrared rays, a said medical guide wire used in the tomography of the body lumen,
A flexible core;
A first coil portion in which a first element wire having radiopaque properties is spirally wound around a distal end portion of the core portion;
A second coil portion in which a second wire is spirally wound around the core portion closer to the core than the first coil portion;
Together covering the second coil portion, a resin layer having an infrared transparent which transmits the infrared irradiated from the light irradiation unit during the tomography,
With
The wire diameter of the second strand is smaller than the wire diameter of the first strand, and the gap between the second strands is larger than the gap between the first strands,
Said second wire in the core and the second coil portion, with has a portion for shielding the infrared rays irradiated from the light irradiation unit during the tomography, the in the second coil portion the gap between the second wire, the infrared irradiated from the light irradiation unit during the tomography, medical guide wire adapted to transmit without being interrupted. The medical guidewire according to claim 1, wherein a gap between the second wires in the second coil portion is at least 2.1 times an outer diameter of the second wires. The medical guidewire according to claim 1, wherein an outer diameter of the core is 250 μm or less. The medical guidewire according to any one of claims 1 to 3, wherein the resin layer is formed of a UV curable resin.

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