JP2016123742A - Long body for medical purpose - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further improve delivery performances in a lumen of a living body.SOLUTION: A long body 10 for medical purposes includes a shaft 12 including an inner tube-side lumen 26 for storing a guide wire G and a distal opening 26b for delivering the guide wire G. The shaft 12 includes a tapered part 34 of which an outer shape is getting narrower toward the distal opening 26b of a delivery distal area 30, and that has a distal apex part 36 at the distal opening 26b. Further, the tapered part 34 includes a distal-side inner peripheral surface 42 that extends from the distal apex part 36 in a proximal direction and is formed in a range shorter than the length along the axial direction of the tapered part 34.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a medical long body that is inserted into a living body lumen through a guide wire.

  Medical long bodies such as catheters are used for treatment and examination in a body lumen such as blood vessels. A catheter usually includes a guide wire lumen (lumen) that accommodates a guide wire and a tip opening that delivers the guide wire, and the tip moves along the guide wire delivered from the tip opening. To the desired location. Therefore, the catheter is required to have a delivery performance that can move smoothly in the blood vessel.

  For example, Patent Document 1 discloses a structure (also referred to as a distal tip) in which a soft polyamide that is softer than the proximal end body portion is provided at the distal end portion of the catheter in order to improve the delivery performance of the catheter.

JP 63-181772 A

  By the way, it is preferable that the distal end portion of the catheter is formed as thin as possible so that it can be pushed into a narrow portion (including a stenosis portion) in a blood vessel at the time of delivery. However, the distal end opening of the catheter is formed to have an inner diameter larger than the outer diameter of the guide wire in order to smoothly move the guide wire in and out. Further, the distal end portion of the catheter is formed to have an appropriate thickness and flexibility so that it can withstand the friction with the blood vessel and the deformation load from the blood vessel (see FIG. 2 of Patent Document 1). For these reasons, the distal end portion of a conventional catheter is set to have a certain thickness, and causes a decrease in delivery performance particularly when delivered to a narrow spot.

  The present invention has been made in order to solve the above-described problems, and the delivery performance in a living body lumen is formed by forming the distal end opening for sending the guide wire and the outer periphery thereof as small as possible. An object of the present invention is to provide a medical elongate body that can further enhance the above.

  In order to achieve the above object, the present invention provides a medical elongated body comprising a body portion including a lumen that accommodates a guide wire, and a distal end opening that is connected to the lumen and delivers the guide wire. The distal end region of the main body includes a tapered portion whose outer diameter decreases toward the distal end opening, and the tapered portion includes a distal end apex at the distal end opening, and further includes a base from the distal end top of the tapered portion. An inner peripheral surface extending in the end direction and formed in a range shorter than the length along the axial direction of the tapered portion is provided.

  According to the above, the medical elongated body includes an inner peripheral surface that extends in the proximal direction from the distal end top portion of the tapered portion and is formed in a range shorter than the length along the axial direction of the tapered portion. Thus, the inner peripheral surface comes into surface contact with the guide wire in the inserted state of the guide wire. Thereby, the taper portion can sufficiently obtain the strength of the tip region in a state where the taper portion is in surface contact with the guide wire. Since the taper portion is narrowed toward the opening of the tip while obtaining the strength of the tip region, the step generated between the guide wire and the outer peripheral surface of the guide wire can be made as small as possible. Therefore, the delivery performance of the medical elongated body is enhanced, and for example, it is possible to smoothly pass through the distal end region even in a narrow portion in the living body lumen.

  In this case, the tip region includes an inner layer that lowers the sliding resistance of the guide wire, an intermediate layer that is provided outside the inner layer and is more flexible than the inner layer, and an intermediate layer that is provided outside the intermediate layer. It is preferable that the inner circumferential surface includes at least the inner layer.

  As described above, since the region has the inner layer, the intermediate layer, and the outer layer, the medical elongated body can easily push the inner peripheral surface radially outward by the flexibility of the intermediate layer when the guide wire is passed through the inner peripheral surface. Can be spread. In addition, the inner layer lowers the sliding resistance of the guide wire and makes the guide wire delivered more smoothly.

  And the front-end | tip part of the said intermediate | middle layer is good to be provided to the position exceeding the base end part of the said internal peripheral surface.

  Thus, by providing the intermediate layer up to a position beyond the proximal end portion of the inner peripheral surface, the medical elongated body can deform the inner peripheral surface more radially outward.

  The inner peripheral surface preferably includes at least one of the intermediate layer and the outer layer.

  Thus, when the inner peripheral surface includes at least one of the intermediate layer and the outer layer, the medical elongated body can prevent the hard inner layer from being exposed from the outer peripheral surface of the tapered portion. Therefore, it can suppress that a tip region damages a living body lumen.

  Furthermore, it is preferable that a lip of the tip opening is constituted by the outer layer.

  Thus, the outer layer harder than the intermediate layer is arranged at the boundary portion with the outer peripheral surface of the guide wire because the lip of the tip opening is constituted by the outer layer. Accordingly, the outer layer can suppress the taper portion from being curled or crushed.

  Still further, the tip region is located on the tip side of a tubular body having the inner layer, the intermediate layer and the outer layer and extending in the axial direction, and the cross-sectional area of the intermediate layer in the tip region is the tube It is preferable that it is larger than the cross-sectional area of the intermediate layer on the base end side.

  Thus, when the cross-sectional area of the intermediate layer in the distal end region is larger than the cross-sectional area on the tube base end side, the inner peripheral surface of the distal end region can be more easily pushed radially outward.

  In addition to the above configuration, the intermediate layer may be provided over the entire circumference in the circumferential direction of the tubular body, and the cross-sectional area may gradually increase from the tubular body proximal side toward the distal direction.

  Thus, the structure in which the cross-sectional area of the intermediate layer changes can be easily manufactured by providing the intermediate layer over the entire circumference of the tubular body. In addition, since the intermediate layer gradually increases, the physical properties of the tubular body can be gradually changed to prevent a decrease in delivery performance due to a sudden physical property change.

  Or the said intermediate | middle layer is provided with two or more along the circumferential direction of the said tubular body as a linear layer extended in the axial direction of the said tubular body, and the sum total of the cross-sectional area is a distal direction from the said tubular body base end side. It is good also as a structure which becomes large gradually toward it.

  As described above, even when a plurality of intermediate layers are provided in the circumferential direction of the tubular body as the striated layer, the diameter of the inner peripheral surface can be increased, and the axial strength of the region can be increased.

  Here, the elongate medical body has an expandable / contractible body that can be expanded and contracted on the proximal end side of the distal end region, and the outer layer and the material constituting the expandable / contractable body are preferably made of the same material.

  Thus, the outer layer and the expansion / contraction body are made of the same material, so that the outer layer and the expansion / contraction body can be easily fused.

  In addition, the inner peripheral surface may be formed to be thin along the axial direction of the lumen in parallel or toward the distal end, and to form an acute angle with the outer peripheral surface of the tapered portion.

  In this way, by forming an acute angle between the inner peripheral surface and the outer peripheral surface of the tapered portion, the step with the guide wire can be further reduced.

  According to the present invention, the medical elongated body can further improve the delivery performance in the living body lumen by forming the distal end opening for sending the guide wire and the outer periphery thereof as small as possible. .

It is a fragmentary side sectional view showing the whole medical elongated body composition concerning one embodiment of the present invention. It is side surface sectional drawing which expands and shows the delivery front-end | tip area | region of the medical elongate body of FIG. 3A is a sectional view taken along line IIIA-IIIA of the inner tube of FIG. 1, FIG. 3B is a sectional view taken along line IIIB-IIIB of the inner tube of FIG. 1, and FIG. 3C is a sectional view taken along line IIIC- It is a IIIC line sectional view. 4A is a cross-sectional view of a position corresponding to FIG. 3A of the inner tube according to the first modification, and FIG. 4B is a cross-sectional view of a position corresponding to FIG. 3B of the inner tube according to the first modification. FIG. 4C is a cross-sectional view of a position corresponding to FIG. 3C of the inner tube according to the first modification. FIG. 5A is a side sectional view showing a delivery tip region according to a second modification, FIG. 5B is a side sectional view showing a delivery tip region according to a third modification, and FIG. 5C is a fourth modification. It is side surface sectional drawing which shows the delivery front-end | tip area | region which concerns on.

  Hereinafter, preferred embodiments of the medical elongated body according to the present invention will be described and described in detail with reference to the accompanying drawings.

  The medical long body 10 according to the present invention is configured, for example, as a hollow catheter and is used for a biological lumen interventional procedure. The type of catheter is not particularly limited. For example, a guiding catheter, an imaging catheter, an ultrasonic catheter, a balloon catheter, an atherectomy catheter, an endoscopic catheter, a stent or other indwelling delivery catheter, or for drug administration Examples thereof include a catheter, an embolization catheter, a microcatheter, and a sheath (for example, a guiding sheath). Hereinafter, the balloon catheter 10 will be described as an example of the medical long body 10.

  The balloon catheter 10 (hereinafter, also simply referred to as “catheter 10”) performs treatments such as expanding a lesion (such as a stenosis) occurring in a blood vessel or applying a drug. The living body lumen in which the medical long body 10 is used is not particularly limited, and examples thereof include a bile duct, trachea, esophagus, urethra, nasal cavity, and other organs in addition to blood vessels.

  As shown in FIG. 1, the catheter 10 includes a long shaft 12 (main body portion) and a hub 14 connected to the proximal end side of the shaft 12. The shaft 12 is a flexible tube that is inserted into a blood vessel during a procedure, and the hub 14 is a proximal portion having rigidity for an operator to operate the shaft 12 inserted into the blood vessel.

  The hub 14 of the catheter 10 transmits the advance / retreat operation and the rotation operation by the operator to the distal end (terminal) side of the shaft 12 by firmly fixing the proximal end portion of the shaft 12 inside. The hub 14 is formed to have a larger diameter than the shaft 12 so that the operator can easily grasp it. The hub 14 has a hollow portion 16 therein and a proximal end opening 16 a communicating with the hollow portion 16. An expansion / contraction operation device (not shown) such as a syringe for expanding or contracting a balloon 18 (expansion / contraction body) provided on the shaft 12 is connected to the proximal end opening 16a.

  The shaft 12 fixed to the hub 14 is set to an appropriate total length so that the proximal end side and the hub 14 are exposed outside the patient's body. The catheter 10 is preferably provided with a plurality of shafts 12 having different lengths within a range of about 300 to 2000 mm, for example, and can be arbitrarily selected by the operator.

  On the distal end side of the shaft 12, a balloon 18 that is a treatment portion for treating a lesioned portion is provided. The balloon 18 is in a contracted state when the shaft 12 moves in the blood vessel, and when the operator operates after reaching the lesioned part, the balloon 18 is expanded in the radially outward direction of the shaft 12.

  The shaft 12 is configured in a coaxial double tube structure (dual lumen catheter) of the outer tube 20 and the inner tube 22 in order to perform the operation of the balloon 18 described above. The outer tube 20 is a tube that constitutes the outer shape of most of the shaft 12, and the inner tube 22 is a tube that is formed narrower than the outer tube 20 and provided inside the distal end side of the outer tube 20.

  The outer tube 20 is formed slightly shorter than the entire length of the shaft 12, and the hub 14 is fixed to the outer peripheral surface on the base end side. The outer tube 20 is formed to have an outer diameter smaller than the inner diameter of the blood vessel to be inserted, and extends from the hub 14 in the distal direction. For example, the outer tube 20 may have a shape such that the diameter gradually decreases in the distal direction.

  The material constituting the outer tube 20 is particularly limited as long as it can be set to physical properties (flexibility, rigidity, elasticity, kink resistance, wear resistance, slipping property, hygiene, etc.) that can deliver the shaft 12 in the blood vessel. However, an appropriate resin material or metal material may be selected.

  For example, the resin material constituting the outer tube 20 may be a polyolefin resin such as high density polyethylene, polypropylene, polybutene, vinyl chloride, ethylene-vinyl acetate copolymer or the like, or a polyolefin elastomer, a fluorine resin or a fluorine elastomer. , Methacrylic resin, polyphenylene oxide, modified polyphenylene ether, polyethylene terephthalate, polybutylene terephthalate, polyether ether ketone, polyamide imide, polyether imide, polyether sulfone, cyclic polyolefin, polyurethane elastomer, polyester elastomer, polyamide or polyamide elastomer , Polycarbonate, polyacetal, styrene resin or styrene elastomer, thermoplastic Polyimide and the like.

  Further, for example, the metal material constituting the outer tube 20 includes a pseudoelastic alloy (including a superelastic alloy) such as a Ni-Ti alloy, a shape memory alloy, stainless steel (for example, SUS304, SUS303, SUS316, SUS316L, SUS316J1, SUS316J1L, SUS405, SUS430, SUS434, SUS444, SUS429, SUS430F, SUS302, and all other SUS types), cobalt-based alloys, precious metals such as gold and platinum, tungsten-based alloys, carbon-based materials (including piano wires) Etc.

  In FIG. 1, the outer tube 20 made of one material is shown. However, the structure of the outer tube 20 is not limited to this, and a multilayer structure in which materials having different functions in the radial direction are stacked. Also good. Furthermore, it is good also as one tube by connecting different materials on the axial direction of the outer tube 20.

  An outer tube side lumen 24 is provided inside the outer tube 20 along the axial direction of the outer tube 20. The proximal end of the outer tube side lumen 24 communicates with the hollow portion 16 of the hub 14, and fluid supplied from the hollow portion 16 (for example, a balloon expansion fluid such as a contrast medium, a priming solution) is supplied to the distal end of the outer tube 20. Flow in the direction.

  A distal end opening 24 a communicating with the outer tube side lumen 24 is provided at the distal end of the outer tube 20. The proximal end portion 18a of the balloon 18 is fixed to the outer peripheral surface of the wall portion constituting the distal end opening 24a by an appropriate joining means (thermal fusion or adhesion using an adhesive).

  Further, an inner tube 22 is provided in the outer tube side lumen 24 on the distal end side of the outer tube 20. The proximal end of the inner tube 22 is joined to a wall portion at an intermediate position of the outer tube 20 so as to penetrate the outer tube 20. The inner tube 22 is curved in the vicinity of the joint, the axis of the inner tube is coaxial with the axis of the outer tube 20, extends in the distal direction in the outer tube 20, and further extends from the distal end opening 24 a of the outer tube 20. A tip portion of the shaft 12 is configured. The inner tube 22 is formed to have an outer diameter smaller than the inner diameter of the outer tube side lumen 24, and the thickness thereof is constant in the axial direction. The inner tube 22 may vary in thickness in the axial direction, for example, the proximal end side is thicker and the inner tube 22 is thinner toward the distal end side.

  Inside the inner tube 22, an inner tube side lumen 26 (lumen) is provided along the axial direction of the inner tube 22. A proximal end opening 26 a and a distal end opening 26 b communicating with the inner tube side lumen 26 are provided at the proximal end and the distal end of the inner tube 22.

  A guide wire G for guiding the catheter 10 in the blood vessel is inserted into the inner tube side lumen 26. That is, in the catheter 10, the guide wire G is inserted near the distal end of the shaft 12 (where the inner tube 22 is installed), and the guide wire G is exposed from the proximal end opening 26 a formed on the side surface of the outer tube 20. It is configured as a rapid exchange type. The catheter 10 to which the present invention can be applied is not limited to the above configuration, and may be an over-the-wire type in which the guide wire G is inserted from the distal end of the shaft 12 to the proximal end of the hub 14.

  A distal end portion 18 b of the balloon 18 is fixed to the outer peripheral surface on the distal end side of the inner tube 22. The balloon 18 has a bag body in which both ends in the axial direction are fixed to the outer tube 20 and the inner tube 22, and the inside communicates with the distal end opening 24 a of the outer tube 20. Then, the encircling portion 18c connecting the base end portion 18a and the tip end portion 18b of the balloon 18 shifts between a contracted state in contact with or close to the outer peripheral surface of the inner tube 22 and an expanded state in which it is separated from the outer peripheral surface of the inner tube 22. It is free. The transition of the balloon 18 from the contracted state to the expanded state is performed by flowing the balloon expansion fluid from the tip opening 24a.

  The portion of the inner tube 22 that protrudes further to the distal end side than the installation location of the balloon 18 is the most distal end side when the shaft 12 is delivered inside the blood vessel. Hereinafter, the distal end region of the inner tube 22 protruding toward the distal end side from the balloon 18 is referred to as a “delivery distal end region 30”.

  As shown in FIG. 2, the delivery distal end region 30 includes a parallel portion 32 extending parallel to the axial direction of the shaft 12 and a tapered portion 34 that continues to the distal end of the parallel portion 32 and narrows toward the distal end direction. The outer diameter of the parallel portion 32 matches the outer diameter of the inner tube 22 on the proximal side with respect to the delivery distal end region 30. The inner diameter of the inner peripheral surface of the parallel portion 32 also coincides with the inner diameter of the inner tube 22 on the proximal side with respect to the delivery distal end region 30 and is set larger than the outer diameter of the guide wire G.

  The tapered portion 34 is a portion that is located at the forefront of the shaft 12 and is formed in a tapered shape. The outer peripheral surface 34a of the tapered portion 34 is inclined at a predetermined angle (for example, 10 ° to 45 °) with respect to the axis of the inner tube 22 in a cross-sectional view. Further, the outer peripheral surface 34a of the tapered portion 34 extends linearly from a connection point 33a with the parallel portion 32 in a cross-sectional view, and forms a distal end opening 26b of the inner tube 22 at the distal end top portion 36 (mouth edge). ing. In addition, the outer peripheral surface 34a may have not only a linear cross-sectional shape but also a cross-sectional shape that draws an arc shape.

  The inner peripheral surface 38 of the tapered portion 34 is bent and connected to the distal end of the inner peripheral surface 32a of the parallel portion 32, and has a funnel-like proximal inner peripheral surface 40 that narrows the distal end side of the inner tube side lumen 26, and a proximal end side. A distal end side inner circumferential surface 42 which is bent at the distal end of the inner circumferential surface 40 and extends in the distal direction. The proximal inner circumferential surface 40 is inclined at the same angle as the outer circumferential surface 34a of the tapered portion 34, and the tapered portion 34 has a constant thickness.

  The distal end side inner peripheral surface 42 is formed with a cylindrical hollow portion 44 that is thinner than the guide wire G at the distal end portion of the inner tube side lumen 26 when the guide wire G is not inserted. That is, from the bend point 33b connected to the proximal inner circumferential surface 40 of the delivery distal end region 30 to the distal end opening 26b, the inner diameter is smaller than the outer diameter of the guide wire G and extends in parallel to the axial direction of the shaft 12. . Therefore, in the state where the guide wire G is inserted into the inner tube side lumen 26, the outer peripheral surface OG of the guide wire G contacts the distal end side inner peripheral surface 42 and pushes outward in the radial direction. In other words, the guide wire G is sent out from the distal end opening 26b of the inner tube 22 while being in surface contact with the distal end side inner peripheral surface 42 (see also FIG. 1).

  Moreover, the outer peripheral surface 34a of the taper part 34 and the front end side inner peripheral surface 42 form the tip apex part 36 at an acute angle by the point where they intersect each other. Therefore, in a state where the outer peripheral surface OG of the guide wire G and the front end side inner peripheral surface 42 are in surface contact, a state in which there is almost no step at the boundary between the outer peripheral surface OG of the guide wire G and the outer peripheral surface 34a of the tapered portion 34 is constructed. The

Hereinafter, an example of the dimensions of the delivery tip region 30 will be described. The inner diameter D _I of the tip side inner circumferential face 42, although depending on the outside diameter D _G of the guide wire G, for example, when the outer diameter D _G of the guide wire G is 0.35 mm, 0.3 mm ≦ D _I It is preferable to set it to ≦ 0.35 mm. In this way the inner diameter D _I of the tip side inner circumferential face 42 is smaller than the outer diameter D _G of the guide wire G, the generation of the clearance is eliminated in a state of inserting the guide wire G in the cavity 44. The inner diameter D _I of the tip side inner circumferential face 42 a guide for wire not extremely smaller than the outer diameter D _O of G, it is possible to suppress a load applied therebetween of the inner tube 22 or guide wire G. Incidentally, the leading end side inner peripheral surface 42 has an inner diameter D _I guidewire be coincident with the outer diameter D _G of the G guidewire G in surface contact with the outer peripheral surface OG of. In this case, since the contact pressure between the distal end side inner circumferential surface 42 and the outer circumferential surface OG of the guide wire G is suppressed, the elastic force of the delivery distal end region 30 may be low.

Further, the distal end side inner peripheral surface 42 is preferably set such that the axial length L _f from the distal end opening 26b to the bending point 33b is 0 mm <L _f ≦ 3 mm. Thereby, since the catheter 10 has the range which surface-contacts with respect to the outer peripheral surface OG of the guide wire G, the intensity | strength of the taper part 34 becomes high and the delivery performance of the catheter 10 improves. Further, the contact range with the guide wire G is not lengthened, and the guide wire G can be satisfactorily delivered.

Further, the outer diameter D _O of the tip apex portion 36 (outer peripheral surface 34a) of the tapered portion 34 is preferably a dimension that is not substantially different from the inner diameter D _{I of the} front end side inner peripheral surface 42, for example, D _O = D _I +0 mm˜ It is preferable to satisfy the relationship of 0.06 mm. Thereby, since the level | step difference between the outer peripheral surface OG of the guide wire G and the outer peripheral surface 34a of the delivery front-end | tip area | region 30 can be eliminated, the catheter 10 can be advanced satisfactorily even in a thin blood vessel.

  And the delivery front-end | tip area | region 30 (inner pipe | tube 22) is the structure which promotes the elastic deformation to the radial direction of the taper part 34 (namely, front end side inner peripheral surface 42) in the insertion state of the guide wire G. Specifically, the inner tube 22 is formed in a multilayer structure including the inner layer 50, the intermediate layer 52, and the outer layer 54 by using a plurality of constituent materials having different functions.

  The inner layer 50 of the inner tube 22 is a layer constituting an inner peripheral surface that directly surrounds the inner tube side lumen 26. The inner layer 50 has a function of reducing the sliding resistance (increasing sliding property) of the guide wire G accommodated in the inner tube side lumen 26. The inner layer 50 is formed with the same thickness along the axial direction of the inner tube 22, and extends from the base end edge 22 a constituting the base end opening 26 a to a midpoint of the distal end side inner peripheral surface 42 of the tapered portion 34. Yes. Since the friction of the guide wire G is reduced even when it contacts the inner layer 50, the guide wire G can be easily moved relative to the shaft 12.

  Further, the inner peripheral surface 42 of the distal end side of the delivery distal end region 30 forms an inner layer 50 from the curved point 33b to a midway position toward the distal end opening 26b, so that the intermediate layer 52 is closed by the inner layer 50 and the outer layer 54, and the inner end surface side. The configuration is such that the peripheral surface 42 is not exposed. Thereby, in the formation position of the front end side inner peripheral surface 42, the contact range of the inner layer 50 with respect to the outer peripheral surface OG of the guide wire G widens, and the guide wire G can be taken in and out more smoothly.

  The material constituting the inner layer 50 is not particularly limited. For example, polytetrafluoroethylene (PTFE), tetrafluoroethylene / ethylene copolymer (ETFE), tetrafluoroethylene / hexafluoropropylene copolymer ( Examples thereof include resin materials such as fluorine-based resins such as FEP), high-density polyethylene (HDPE), polyacetal (POM), polyphenylene sulfide (PPS), polyolefin-based resins, and super engineering plastics. The inner layer 50 may be formed by blending a predetermined resin material with a lubricant. In the present embodiment, the inner layer 50 is made of PTFE.

  The intermediate layer 52 of the inner tube 22 is a layer that is provided outside the inner layer 50 and has more flexibility than the inner layer 50. The intermediate layer 52 enhances the elasticity of the inner tube 22 and softens the tapered portion 34 (the distal end opening 26b and the distal end inner peripheral surface 42) of the delivery distal end region 30 to promote elastic deformation outward in the radial direction. It has a function.

  In particular, the intermediate layer 52 according to the present embodiment provides a sufficient elastic deformation force to the tapered portion 34 by the tip portion extending to the tip side beyond the bending point 33b of the tip side inner peripheral surface 42. ing. Further, the thickness of the intermediate layer 52 is provided so as to gradually increase from the base end edge 22a of the inner tube 22 toward the tip end portion. That is, in the delivery tip region 30 shown in FIG. 3A, the taper portion 34 is more easily deformed by the thick intermediate layer 52 having flexibility.

  Further, as shown in FIG. 3B, the intermediate layer 52 is made thinner than the delivery tip region 30 at the place where the balloon 18 is installed, so that the inner layer 22 can be easily bent appropriately. Therefore, the occurrence of kinks in the inner tube 22 is suppressed, and even if the inner tube 22 is bent, the restoration can be performed smoothly.

  Furthermore, as shown in FIG. 3C, the intermediate layer 52 is thinner than the installation location of the balloon 18 on the proximal end side connected to the outer tube 20. For this reason, swinging of the inner tube 22 with respect to the outer tube 20 can be suppressed.

  The material constituting the intermediate layer 52 is not particularly limited, but an elastomer made of polyvinyl chloride elastomer, olefin elastomer, polyester elastomer, polyamide elastomer, polyurethane elastomer, styrene elastomer, or a mixture thereof. Alternatively, various rubber materials such as natural rubber, isoprene rubber, butyl rubber, chloroprene rubber, nitrile-butadiene rubber, styrene-butadiene rubber, and silicone rubber can be used. In the present embodiment, the intermediate layer 52 is made of a polyurethane elastomer.

  On the other hand, the outer layer 54 of the inner tube 22 is a layer that is provided outside the intermediate layer 52 and constitutes the appearance of the inner tube 22. The outer layer 54 is formed so as to be more flexible than the inner layer 50 and more rigid (rigid) than the intermediate layer 52. Thereby, while the tip of the shaft 12 is moderately flexible, the tolerance of the outer peripheral surface is enhanced, and the delivery performance in the blood vessel (permeability to the stenosis, etc.) is improved.

  This outer layer 54 extends from the proximal edge 22 a to the distal apex 36 of the delivery distal region 30. The thickness of the outer layer 54 is provided so as to gradually decrease from the proximal end edge 22a of the inner tube 22 toward the distal end portion, contrary to the thickness of the intermediate layer 52. More specifically, as shown in FIG. 3A, the delivery tip region 30 is formed so as to be thin, and is configured to easily exert the elastic force of the intermediate layer 52. That is, the wall portion where the distal end side inner peripheral surface 42 is formed has a large diameter in the insertion state of the guide wire G into the cavity portion 44 by covering the intermediate layer 52 with a small amount of the outer layer 54 while occupying a large amount of the intermediate layer 52. It becomes easy to be elastically pushed outward in the direction. Further, since the outer layer 54 covers the intermediate layer 52, the entire delivery tip region 30 is protected by the outer layer 54, and the delivery performance of the shaft 12 can be enhanced.

  Further, as shown in FIG. 3B, the outer layer 54 is thicker than the delivery tip region 30 at the installation location of the balloon 18, thereby increasing the rigidity of the inner tube 22 and cooperating with the intermediate layer 52. This improves the shape maintenance power. Therefore, the balloon 18 can be supported firmly and the treatment at the time of expansion can be carried out satisfactorily.

  Further, as shown in FIG. 3C, the outer layer 54 is thicker than the installation location of the balloon 18 on the proximal end side connected to the outer tube 20, thereby increasing the rigidity of the proximal end portion of the inner tube 22. Thus, the supporting force of the inner tube 22 with respect to the side surface of the outer tube 20 can be increased.

  The material constituting the outer layer 54 is not particularly limited, but polyolefin (for example, polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or two or more of these) And the like, and polymer materials such as polystyrene, polyvinyl chloride, polyamide, polyester, polyurethane, polyimide, fluororesin, and mixtures thereof. In particular, since the outer layer 54 constitutes the outer peripheral surface of the inner tube 22, the outer layer 54 may be selected so as to include the constituent material of the balloon 18 so as to be easily fused with the balloon 18. In this embodiment, the outer layer 54 is also made of polyamide based on the fact that the balloon 18 is made of polyamide.

  The inner tube 22 of the catheter 10 is formed in the above laminated structure. Here, when the hardness of each layer is simply compared by the properties of the applied resin, the intermediate layer 52 <outer layer 54 <inner layer 50 is basically increased in this order. In addition to the order of the intermediate layer 52 <the outer layer 54 <the inner layer 50, the hardness of each layer may be the intermediate layer 52 <the inner layer 50 <the outer layer 54, and the intermediate layer 52 <the inner layer 50 = the outer layer 54. It may be. For example, if the inner layer 50 is more flexible than the outer layer 54, the diameter of the tip opening 26b can be more easily promoted. In this case, the inner layer 50 may be configured by blending a lubricant that lowers the sliding resistance of the guide wire G.

  The inner tube 22 is not limited to the three-layer structure of the inner layer 50, the intermediate layer 52, and the outer layer 54, and the distal end opening 26b and the distal end inner peripheral surface 42 of the delivery distal end region 30 can be expanded in the radial direction. Various structures (single layer, two layers, or four or more layers) may be employed. The inner tube 22 is not only configured to gradually change the thickness of the intermediate layer 52 and the outer layer 54 along the axial direction of the inner tube 22, but also configured to change stepwise with a predetermined position in the axial direction as a boundary. But you can. For example, the intermediate layer 52 may be provided between the inner layer 50 and the outer layer 54 only in the delivery tip region 30, and only the inner layer 50 and the outer layer 54 may be configured in the installation location of the balloon 18 or in the outer tube 20. Further, the delivery tip region 30 may be configured to be fixed to the tip of the shaft 12 as a separate member (tip tip) as well as being integrally formed with the inner tube 22.

  The catheter 10 according to the present embodiment is basically configured as described above, and the operation and effect thereof will be described below.

The catheter 10 is delivered to a lesion in a blood vessel under the guidance of the guide wire G in a state where the guide wire G is inserted into the inner tube side lumen 26 of the shaft 12 and delivered from the distal end opening 26b as described above. The delivery tip region 30 of the catheter 10 according to this embodiment, since the front end side inner circumferential surface 42 becomes smaller inner diameter D _I than the outer diameter D _G of the guide wire G, as shown in FIG. 1 In the inserted state of the guide wire G, the distal inner circumferential surface 42 comes into surface contact with the guide wire G. On the other hand, the outer peripheral surface 34a of the taper portion 34 has a smaller diameter toward the tip opening 26b. For this reason, there is almost no step between the outer peripheral surface OG of the guide wire G and the outer peripheral surface 34a of the tapered portion 34 (the step is made as small as possible).

  Here, in the conventional catheter, it is assumed that the guide wire lumen into which the guide wire G is inserted is formed to have a larger diameter than the guide wire G. In this case, not a few steps are formed between the outer peripheral surface OG of the guide wire G and the outer peripheral surface of the delivery tip region of the catheter. This level | step difference may be caught in the fine location of the blood vessel at the time of the delivery of a catheter, and causes a fall in delivery performance.

  On the other hand, the catheter 10 according to the present embodiment has a shape in which the delivery tip region 30 is sufficiently tapered (inclined) toward the axial guide wire G, and has as few steps as possible. Therefore, for example, a delivery performance that can pass smoothly even in a stenotic part having a high strength in a blood vessel is obtained. Since the shaft 12 has a thickness that makes surface contact with the guide wire G and constitutes the tapered portion 34, the strength of the delivery tip region 30 can be sufficiently secured.

  In addition, since the delivery tip region 30 has the inner layer 50, the intermediate layer 52, and the outer layer 54, when the guide wire G is passed through the tip side inner peripheral surface 42, the tip side inner peripheral surface 42 is radially moved by the elastic force of the intermediate layer 52. Can be easily pushed outward. The inner layer 50 lowers the sliding resistance of the guide wire G, so that the guide wire G can be delivered more smoothly. By providing the intermediate layer 52 up to a position where it overlaps the distal end inner peripheral surface 42, the catheter 10 deforms the distal end inner peripheral surface 42 well outward in the radial direction while suppressing the collapse of the shape of the tapered portion 34. Let

  Furthermore, since the distal inner circumferential surface 42 is constituted by the inner layer 50 and the outer layer 54, the catheter 10 can prevent the inner layer 50 from being exposed from the outer circumferential surface 34a of the tapered portion 34, and the inner layer 50 is formed to be hard. Even in this case, it is possible to avoid contact with blood vessels. Since the tip apex portion 36 of the tip opening 26b is constituted by the outer layer 54, the outer layer 54 is disposed at the boundary portion with the outer peripheral surface OG of the guide wire G. The outer layer 54 can suppress the taper portion 34 from being curled or crushed.

  Furthermore, since the intermediate layer 52 is provided over the entire circumference of the inner tube 22, a structure in which the cross-sectional area of the intermediate layer 52 changes can be easily manufactured. Moreover, since the intermediate | middle layer 52 becomes large gradually, the physical property of the catheter 10 can be changed gradually, and the fall of the delivery performance by a sudden physical property change can be prevented.

  In addition, the medical elongate body 10 is not limited to said embodiment, A various application example and a modification can be taken. For example, the medical elongate body 10 includes not only a catheter but also various treatment devices that are guided to a desired location in a living body lumen by a guide wire G to perform treatment or diagnosis. In short, the above-described configuration can be applied to a portion where the guide wire G is sent out in the medical long body 10.

  Hereinafter, some modified examples of the medical elongated body 10 will be specifically described with reference to FIGS. 4A to 5C. In addition, in the following description, the same code | symbol as this embodiment is attached | subjected to the structure same as the medical elongate body 10 which concerns on this embodiment, or the structure which has the same function, and it abbreviate | omits about the detailed description.

  In the inner tube 60 according to the first modification, the intermediate layer 52 is formed on the filament layer 62 in the laminated structure including the inner layer 50, the intermediate layer 52, and the outer layer 54 as shown in the cross-sectional views of FIGS. 4A to 4C. This is different from the inner tube 22 according to this embodiment. The linear layer 62 extends from the base end edge 22a to the middle position of the tapered portion 34 along the axial direction of the inner tube 60, and a plurality (eight in this embodiment) are provided along the circumferential direction of the inner layer 50. Yes. The outer layer 54 is provided outside the filament layer 62 and between the two filament layers 62 so as to cover the filament layer 62.

  Each linear layer 62 is formed so that the cross-sectional area on the base end edge 22a side is small and the cross-sectional area gradually increases in the distal direction. By forming in this way, a rapid change in physical properties of the inner tube 22 can be suppressed. Further, in the taper portion 34, the distal end side inner peripheral surface 42 can be favorably elastically deformed in the radial direction by the thick (large cross-sectional area) linear layer 62.

  As shown in FIG. 5A, the inner tube 70 according to the second modified example has an axial center of the inner tube 70 on the distal end side inner peripheral surface 72 from the bending point 33b toward the distal end opening 26b in a state where the guide wire G is not inserted. This is different from the inner tube 22 according to the present embodiment in that the shape is inclined to the side. Even with this configuration, in the inserted state of the guide wire G (see the two-dot chain line in FIG. 5A), the distal end inner peripheral surface 72 is pushed forward and radially outward with the curved point 33b as a base point. The tip side inner circumferential surface 72 and the outer circumferential surface OG of the guide wire G can be brought into surface contact.

  As shown in FIG. 5B, the inner tube 80 according to the third modification is configured so that the inner layer 50 extends to the tip top 36 where the outer layer 54 extends, and thus the inner tube 22 according to the present embodiment. And different. That is, the inner peripheral surface 82 on the tip end side is almost entirely composed of the inner layer 50, and the outer layer 54 is a slight portion. Thus, by providing the lubricous inner layer 50 up to the tip apex 36, the slidability of the guide wire G can be further enhanced. Further, since the tip apex portion 36 is covered by the outer layer 54, the resistance of the inner tube 80 to the blood vessel can be increased as in the present embodiment.

  As shown in FIG. 5C, the inner tube 90 according to the fourth modification has an inner tube 22 according to the present embodiment in that the distal end side inner peripheral surface 92 is constituted by an inner layer 50, an intermediate layer 52, and an outer layer 54. And different. Thus, even if the tip side inner peripheral surface 92 is configured in three layers, substantially the same effect as that of the inner tube 22 of the present embodiment can be obtained. Further, by cutting the inner tube 90 having a three-layer structure, the distal end side inner peripheral surface 92 can be easily configured, so that the manufacturing operation of the catheter 10 can be simplified and the manufacturing cost can be reduced.

  Alternatively, the delivery tip region 30 of the catheter 10 may constitute the outer peripheral surface 34a of the tapered portion 34 by exposing the flexible intermediate layer 52 having a high elastic force at the tip portion. In short, the structure of the laminated structure constituting the delivery tip region 30 is not particularly limited as long as the step with the outer peripheral surface OG of the guide wire G is reduced as much as possible and the guide wire G can be delivered.

  In the above description, the present invention has been described with reference to preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. Yes.

DESCRIPTION OF SYMBOLS 10 ... Medical long body, balloon catheter 12 ... Shaft 18 ... Balloon 20 ... Outer tube 22, 60, 70, 80, 90 ... Inner tube 26 ... Inner tube side lumen 26b ... Tip opening 30 ... Delivery tip region 32 ... Parallel Portion 34 ... Tapered portion 34a ... Outer peripheral surface 36 ... Top apex 40 ... Base end side inner peripheral surface 42, 72, 82, 92 ... End side inner peripheral surface 50 ... Inner layer 52 ... Intermediate layer 54 ... Outer layer 62 ... Linear layer G ... guide wire

Claims (10)

A medical elongated body comprising a main body including a lumen that accommodates a guide wire and a distal end opening that is connected to the lumen and delivers the guide wire,
The tip region of the main body is
A tapered portion having an outer diameter that decreases toward the tip opening,
The tapered portion includes a tip apex at the tip opening,
The medical length further includes an inner peripheral surface extending in a proximal direction from the tip top of the tapered portion and formed in a range shorter than a length along the axial direction of the tapered portion. Scale. The medical elongated body according to claim 1,
The tip region is
An inner layer for reducing the sliding resistance of the guide wire;
An intermediate layer provided outside the inner layer and having more flexibility than the inner layer;
An outer layer provided on the outer side of the intermediate layer and having a harder property than the intermediate layer, and is formed in a multilayer structure,
The medical peripheral body, wherein the inner peripheral surface includes at least the inner layer. The medical elongated body according to claim 2,
The medical long body, wherein a distal end portion of the intermediate layer is provided to a position exceeding a proximal end portion of the inner peripheral surface. The medical elongated body according to claim 2 or 3,
The inner peripheral surface is configured to include at least one of the intermediate layer and the outer layer. The medical elongated body according to claim 4,
The long edge for medical use, wherein a lip of the distal end opening is constituted by the outer layer. In the medical elongate body of any one of Claims 2-5,
The tip region is located on the tip side of a tubular body that has the inner layer, the intermediate layer, and the outer layer and extends in the axial direction;
The medical elongated body, wherein a cross-sectional area of the intermediate layer in the distal end region is larger than a cross-sectional area of the intermediate layer on the proximal end side of the tubular body. The medical elongated body according to claim 6, wherein
The said intermediate | middle layer is provided over the circumferential direction perimeter of the said tubular body, The cross-sectional area becomes large gradually toward the front end direction from the said tubular body base end side. The medical elongate body characterized by the above-mentioned. The medical elongated body according to claim 6, wherein
The intermediate layer is provided in a plurality along the circumferential direction of the tubular body as a linear layer extending in the axial direction of the tubular body, and the total cross-sectional area is from the proximal end side of the tubular body toward the distal direction. Medical long body characterized by gradual growth. In the medical elongate body of any one of Claims 2-8,
The medical elongated body has an expandable / contractible body that can be expanded and contracted on the proximal end side of the distal end region,
The medical elongate body, wherein the outer layer and the material constituting the expansion / contraction body are made of the same material. In the medical elongate body of any one of Claims 1-9,
The medical inner length is characterized in that the inner peripheral surface is formed to be thin along the axial direction of the lumen in parallel or toward the distal end, and to form an acute angle with the outer peripheral surface of the tapered portion. body.

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