JP2018019729A - Balloon catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a balloon catheter that can have flexibility at a distal end of an inner tube while sufficiently keeping hardness in the inner tube with a simple configuration.SOLUTION: A balloon catheter 100 includes a balloon 110, an outer tube 120, and an inner tube 130. The balloon can be expanded/contracted by introduction and discharge of a pressure medium. The outer tube is arranged at a proximal end side of the balloon and the proximal end part 110a of the balloon is connected to the outer tube. The inner tube is arranged in an inner cavity of the outer tube so as to divide a lumen 133 where a pressure medium can flow with the outer tube and a distal end part 110b of the balloon is connected to the inner tube. The inner tube includes: a first layer 131; and a second layer 132 for covering the first layer. A distal end of the second layer is arranged closer to a proximal end side rather than a distal end of the first layer. The first layer has hardness lower than that of the second layer.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a balloon catheter used for dilating a stenosis.

  There are many tubular organs such as blood vessels, urinary tracts, digestive organs, and other tubular organs such as thoracic cavity, abdominal cavity, nasal cavity, etc., and nutrients, oxygen, etc. pass through these organs to various parts of the body. Delivered. When the circulation of nutrients and oxygen is hindered by a narrowed portion generated in a lumen, a body cavity or the like, each function of the living body is lowered, and various diseases are caused.

  A balloon catheter that introduces a balloon into a stenosis occurring in a lumen, a body cavity or the like and expands the stenosis from the inside to the outside in order to eliminate the stenosis in the living body and treat Used. For example, a balloon catheter is used for percutaneous coronary intervention in which blood flow is improved by pushing a stenosis of a coronary artery with a balloon. The balloon catheter is configured by connecting a balloon to the distal end portion of a long shaft member extending in the axial direction.

  The shaft member includes an outer tube and an inner tube disposed in a lumen of the outer tube, and a lumen through which a pressurized medium for expanding and contracting the balloon can flow between the inner tube and the outer tube. Is partitioned. Since the shaft member is introduced up to the stenosis part in the living body by the user (operator), the stress applied to the living body can be reduced while maintaining sufficient hardness to prevent buckling in the living body. It is necessary to provide flexibility on the tip side.

  Thus, for example, Patent Document 1 below discloses a configuration in which the distal end portion is flexible by inclining the distal end portion of the inner tube of the balloon catheter to reduce the diameter.

  Patent Document 2 below discloses a configuration in which a distal end portion is provided with flexibility by fixing a soft distal tip to the distal end portion of the inner tube of the balloon catheter.

Japanese Patent Laid-Open No. 11-033122 JP 05-192410 A

  However, since the balloon catheter like patent document 1 only made the diameter of the front-end | tip part of the inner tube which consists of a single member thin, it is strong in the part which made the diameter thin, and the part with the original diameter. I can't make enough difference. That is, when the diameter of the distal end portion of the inner tube is reduced, there is no change in the hardness of the material of the distal end portion, so that sufficient flexibility cannot be provided. In addition, in the manufacturing method in which the diameter of the shaft member is reduced by melting the resin by heat that is generally used, the resin becomes more dense by heat, and therefore, it is applied to a material containing a hard resin. It is difficult.

  In addition, the balloon catheter as in Patent Document 2 requires a distal tip as a member separate from the inner tube, and is sufficiently fixed so that the distal tip is not detached from the inner tube due to stress in the living body. Therefore, it becomes a complicated configuration.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a balloon catheter capable of providing flexibility at the distal end portion of the inner tube while sufficiently maintaining the hardness of the inner tube with a simple configuration. And

  A balloon catheter according to the present invention includes an expansion portion that can be expanded and contracted by introduction and discharge of a pressurized medium, and an outer tube that is disposed on the proximal end side of the expansion portion and to which the proximal end portion of the expansion portion is connected. An inner tube disposed in a lumen of the outer tube and defining a lumen through which the pressurized medium can flow between the outer tube and the distal end portion of the expansion portion connected thereto, The inner tube includes a first layer and a second layer covering the first layer, and a distal end of the second layer is disposed on a proximal side with respect to a distal end of the first layer, The first layer has a lower hardness than the second layer.

  According to the balloon catheter according to the present invention, the inner tube includes the first layer, and the second layer having a hardness higher than that of the first layer and disposed closer to the proximal side than the distal end of the first layer. I have. Therefore, the balloon catheter can give flexibility to the distal end portion of the inner tube while sufficiently maintaining the hardness of the inner tube with the simple configuration as described above.

  Further, when the balloon catheter is configured such that the distal end portion of the expansion portion is connected to the first layer, the outer diameter of the distal end portion of the expansion portion is smaller than the outer diameter of the proximal end portion of the expansion portion. The passage of the balloon catheter inside can be improved.

  Further, when the balloon catheter is configured such that the thickness along the radial direction of the distal end portion of the expansion portion is equal to or less than the thickness along the radial direction of the second layer, the maximum outer diameter of the inner tube connecting the distal end portion of the expansion portion is increased. Without introducing it into the living body.

  The balloon catheter may be configured such that the distal end portion of the expansion portion is connected to the proximal end side with respect to the distal end of the first layer. Thereby, the inner tube | pipe can have a site | part which has sufficient softness | flexibility in the front end side rather than the front-end | tip part of an expansion part. For this reason, the balloon catheter which concerns on this invention can reduce the stress received when the front-end | tip part of an inner tube collides with a biological lumen wall, and can prevent peeling from a 1st layer.

  Further, when the balloon catheter is configured to be inclined so that the end surface on the distal end side of the second layer spreads radially outward from the distal end side toward the proximal end side, when the inner tube is introduced into the living body, The inclined end face reduces the level difference and can be smoothly introduced without applying excessive stress to the living body.

  In the balloon catheter, when the first layer is formed with at least one of a convex portion or a concave portion on the inner surface formed in the lumen of the inner tube, the inner surface of the inner tube and a guide wire that passes through the lumen of the inner tube The sliding resistance is reduced, and the guide wire can be easily introduced and removed.

It is a perspective view which shows the state which inserted the guide wire in the balloon catheter which concerns on embodiment. It is a perspective view which shows the principal part of the balloon catheter of FIG. It is a perspective view which shows the balloon catheter of FIG. 2 in a cross section along the AA line in FIG. It is a side view which shows the balloon catheter of FIG. 2 in a cross section along the AA line in FIG. It is a side view which shows the principal part of the balloon catheter of FIG. It is a perspective view which shows the balloon catheter which concerns on the modification of embodiment in a cross section.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. The size and ratio of each member in the drawings are exaggerated for convenience of explanation and may be different from the actual size and ratio. In the balloon catheter, the hand operation unit side operated by the user (operator) is equivalent to the proximal end side, and the balloon side introduced into the patient's living body (blood vessel or the like) corresponds to the distal end side. In all drawings, the balloon catheter is illustrated with the balloon expanded.

  The balloon catheter 100 is introduced into a living body (blood vessel or the like) of a patient and expands a stenosis portion in the blood vessel from the inside to the outside, thereby eliminating the stenosis and treating the stenosis. The balloon catheter 100 includes a balloon 110 corresponding to an expansion portion, an outer tube 120 and an inner tube 130 made of a shaft member, and a hand operation unit 140 that is operated by a user (operator).

  The configuration of the balloon catheter 100 will be described with reference to FIGS.

  FIG. 1 is a perspective view showing a state in which a guide wire 10 is inserted into a balloon catheter 100 according to the embodiment. The guide wire 10 shown in FIG. 1 is not shown on the proximal end side. FIG. 2 is a perspective view showing a main part of the balloon catheter 100 of FIG. FIG. 3 is a perspective view showing the balloon catheter 100 of FIG. 2 in section along the line AA in FIG. 4 is a side view showing the balloon catheter 100 of FIG. 2 in section along the line AA in FIG. FIG. 5 is a side view showing a main part of the balloon catheter 100 of FIG.

  The balloon 110, for example, inflates a stenosis in a patient's blood vessel from the inside to the outside, thereby eliminating the stenosis and restoring the blood flow.

  The balloon 110 is expanded and contracted by introduction and discharge of a pressurized medium. The balloon 110 is formed in a long bag shape from the proximal end portion 110a to the distal end portion 110b. The balloon 110 has a proximal end portion 110a and a distal end portion 110b that are open. The distal end portion 110b of the balloon 110 is connected to the distal end portion 131s of the inner tube 130 so as to seal the outer peripheral edge of the opening. Specifically, the distal end portion 110b of the balloon is connected to the first layer 131 of the inner tube 130 so as to seal the outer peripheral edge of the opening. The proximal end portion 110a of the balloon 110 is connected to the outer tube 120 so as to seal the outer peripheral edge of the opening.

  As shown in FIG. 3, the balloon 110 can introduce a pressurized medium via a lumen 133 between the inner tube 130 and the outer tube 120. The balloon 110 expands when a pressurized medium is introduced, and contracts when the introduced pressurized fluid is discharged. The pressurizing medium is made of, for example, a mixed liquid of contrast medium and physiological saline. The balloon 110 is expanded by introducing a liquid mixture of contrast medium and physiological saline through a lumen 133 from a syringe (not shown) attached to the hand operation unit 140. The expanded balloon 110 is deflated when the contrast medium and physiological saline introduced therein are discharged from the hand operation unit 140 via the lumen 133.

  The pressurizing medium introduced into the balloon 110 is not limited to the mixed liquid of contrast medium and physiological saline. A fluid such as liquid or gas can be applied as the pressurizing medium. As the liquid, for example, a contrast agent, physiological saline, or the like can be used. For example, air, nitrogen, oxygen, carbon dioxide, or the like can be used as the gas.

  The balloon 110 includes, for example, polyethylene, polypropylene, polyolefin such as ethylene-propylene copolymer, polyester such as polyethylene terephthalate, polyvinyl chloride, ethylene-vinyl acetate copolymer, cross-linked ethylene-vinyl acetate copolymer. A thermoplastic resin such as coalescence or polyurethane, polyamide elastomer, silicone rubber, and latex rubber are used. The balloon 110 may be formed in a single layer structure using one kind of the above materials, or may be formed in a laminate structure by combining two or more kinds of the above materials.

  The balloon 110 may be provided with a contrast marker on the inner tube 130 in the balloon 110. The contrast marker is made of an X-ray (radiation) opaque material (for example, gold, platinum, tungsten, or a mixture thereof), and is used to visually recognize the position of the balloon in vivo under X-ray contrast. It is. The contrast marker can be configured in a cylindrical shape (ring shape), for example.

  As shown in FIG. 5, the balloon 110 is formed such that the thickness t1 along the radial direction of the distal end portion 110b is equal to or less than the thickness t2 along the radial direction of the second layer 132 of the inner tube 130. That is, the distal end portion 110 b of the balloon 110 does not protrude outward in the radial direction from the second layer 132 of the inner tube 130 when connected to the first layer 131 of the inner tube 130. Accordingly, the distal end portion 110b of the balloon 110 does not hinder introduction into the blood vessel without increasing the maximum outer diameter of the inner tube 130 (corresponding to the outer diameter of the second layer 132).

  As shown in FIG. 4, the distal end portion 110 b of the balloon 110 is fixed at a position closer to the proximal end than the distal end of the first layer 131. That is, only the first layer 131 of the inner tube 130 exists between the end surface 131 c (tip surface) of the distal end portion 131 s of the inner tube 130 and the distal end portion 110 b of the balloon 110. Therefore, the vicinity of the end surface 131 c of the inner tube 130 is not supported by the balloon 110 in addition to the second layer 132 and has sufficient flexibility. Furthermore, since the distal end portion 110b of the balloon 110 is not connected to the vicinity of the end surface 131c of the inner tube 130, the distal end portion 110b is not directly subjected to pressure when introduced into the blood vessel. Peeling from the first layer 131 can be prevented.

  The shaft member introduces the balloon 110 attached to the distal end side thereof into, for example, a stenosis portion in a blood vessel. The shaft member includes an outer tube 120 and an inner tube 130.

  As shown in FIG. 1, the outer tube 120 is formed in a long shape extending in the axial direction so that it can be introduced into a blood vessel. The outer tube 120 is disposed on the radially outer side of the inner tube 130 via the lumen 133. The distal end portion 120s of the outer tube 120 is disposed on the proximal end side of the balloon 110, and the proximal end portion 110a of the balloon 110 is connected thereto. The proximal end portion 120 a of the outer tube 120 is connected to a hand operation unit 140 that introduces a pressurized medium into the lumen 133.

  As shown in FIG. 1, the outer tube 120 includes a wire port portion 120f. The wire port portion 120f is opened in a circular shape on the outer peripheral surface of the outer tube 120, and is fixed in a state where the proximal end 130a of the inner tube 130 is inserted. In the wire port portion 120f, the end face 131k (base end face) of the first layer 131 and the end face 132k (base end face) of the second layer 132 face the outside. The guide wire 10 is introduced from the end face 131c of the inner tube 130 shown in FIG. 3, and is led out from the wire port portion 120f.

  In order to facilitate exchange of the balloon catheter 100, the wire port part 120f is provided on the distal end side of the shaft member, and is configured as a rapid exchange type in which the guide wire 10 is introduced only to a part of the distal end side of the shaft member. . On the other hand, the wire port portion may be configured as an over-the-wire type that is introduced in the axial direction over the entire length from the proximal end side to the distal end side of the shaft member in order to facilitate replacement of the guide wire 10.

  For the outer tube 120, for example, a flexible hard material, a soft material, or an elastic material is used. Specifically, the material of the outer tube 120 includes, for example, polyvinyl chloride, polyethylene, polypropylene, cyclic polyolefin, polystyrene, poly (4-methylpentene-1), polycarbonate, acrylic resin, acrylonitrile-butadiene-styrene. Various soft or hard resins such as polymers, polyesters such as polyethylene terephthalate, polyethylene naphthalate, butadiene-styrene copolymers, polyamides (for example, nylon 6, nylon 6,6, nylon 6,10, nylon 12), Various rubber materials such as natural rubber, butyl rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, silicone rubber, various thermoplastic elastomers such as polyurethane, polyester, polyamide, olefin, styrene, Stainless steel, as aluminum, various metal materials such as copper or copper-based alloy, various kinds of glass, alumina, various ceramics such as silica.

  As shown in FIGS. 3 and 4, the inner tube 130 is formed in an elongated shape with its distal end 131 b side extending in the axial direction so that it can be introduced into the blood vessel. On the other hand, the base end 130 e side of the inner tube 130 is curved outward in the axial direction and connected to the wire port portion 120 f of the outer tube 120. The inner tube 130 is disposed in the lumen of the outer tube 120. The inner tube 130 defines a lumen 133 through which a pressurized medium can flow between the inner tube 130 and the outer tube 120. The inner tube 130 is connected to the distal end portion 110 b of the balloon 110. The inner tube 130 has a two-layer structure of a first layer 131 and a second layer 132.

  As shown in FIGS. 3 and 4, the first layer 131 has a cylindrical shape and is arranged on the inner surface side forming the lumen of the inner tube 130. A medical long body such as the guide wire 10 is introduced into the lumen of the inner tube 130 formed by the first layer 131. That is, the inside of the first layer 131 constitutes a lumen 131e for the guide wire 10. Further, the tip 131 b of the first layer 131 is disposed on the tip side of the tip 132 b of the second layer 132. The tip 110 b of the balloon 110 is fixed between the tip 131 b of the first layer 131 and the tip 132 b of the second layer 132. The first layer 131 can use the same material as that of the outer tube 120.

  The resin constituting the first layer 131 has a relatively lower hardness than the resin constituting the second layer 132. For this reason, the tip 131s of the inner tube 130 is made of only a resin having low hardness, and thus has flexibility. As a result, the distal end portion 131 s of the inner tube 130 improves the followability with respect to a medical long body such as the guide wire 10 introduced into the lumen of the inner tube 130. For example, when the guide wire 10 is introduced into the inner tube 130, the distal end portion 131s of the inner tube 130 moves flexibly following the movement of the guide wire 10, and the outer surface of the guide wire 10 and the inner surface 131d of the inner tube 130 are moved. Since no clearance is generated between them, the risk of the tip of the inner tube 130 damaging the blood vessel wall can be suppressed.

  As shown in FIGS. 3 and 4, the second layer 132 is formed so as to cover the first layer 131 except for the tip 131 s of the first layer 131. And the front-end | tip 132b of the 2nd layer 132 is arrange | positioned rather than the front-end | tip 131b of the 1st layer 131 at the base end side. For example, the second layer 132 can be formed by covering the entire outer periphery of the first layer 131 and then peeling the tip 132b of the second layer 132 by grinding or cutting. Note that, from the viewpoint of maintaining the hardness of the inner tube 130, the second layer 132 is preferably formed so as to cover the entire surface of the first layer 131 except the tip 131s.

  An end surface 132c on the distal end side of the second layer 132 is inclined so as to spread radially outward from the distal end side toward the proximal end side. Therefore, when the distal end 131b of the inner tube 130 is introduced into the blood vessel, the physical step is reduced by the inclined end surface, and the inner tube 130 can be smoothly introduced into the blood vessel.

  As described above, the inner tube 130 has a first layer 131 (having a relatively low hardness relative to the resin constituting the second layer 132) and a second layer 132 (relative to the resin constituting the first layer 131). The hardness is high). The tip 131s of the inner tube 130 is configured such that the second layer 132 is removed and the first layer 131 is exposed. For this reason, the tip 131s of the inner tube 130 is composed of only the first layer 131 made of a resin having low hardness, and thus has flexibility. That is, the balloon catheter 100 does not need to be provided with a member having flexibility separate from the inner tube 130 in order to make the distal end portion 131s flexible.

  For example, the inner tube 130 may be formed of a nylon elastomer having a Shore D hardness of 62 for the first layer 131 and nylon having a Shore D hardness of 74 for the second layer 132. With this configuration, the tip 131 s of the inner tube 130 can be formed only from the first layer 131 having a Shore D hardness lower than that of the second layer 132. That is, the tip 131s of the inner tube 130 can be provided with flexibility by simply removing the second layer 132 and exposing the first layer 131. For this reason, the balloon catheter 100 can ensure the flexibility of the distal end portion (the distal end portion 131s of the inner tube 130) of the balloon catheter 100 and can maintain the hardness of the inner tube 130 other than the distal end portion 131s of the inner tube 130. Therefore, it is possible to prevent the inside of the living body lumen from being damaged during the delivery of the balloon catheter 100 and to improve the operability of the balloon catheter 100.

  The first layer 131 of the inner tube 130 is preferably made of a resin having a Shore D hardness of less than 71. With this configuration, the flexibility of the first layer 131 of the inner tube 130 can be ensured, and damage to the wall of the living body lumen when the tip 131b of the inner tube 130 collides with the living body lumen can be reduced. Can do. In addition, since the distal end portion 131s of the inner tube 130 has flexibility, followability with respect to a medical long body such as the guide wire 10 introduced into the lumen of the inner tube 130 is improved. Further, in the inner tube 130, the difference in Shore D hardness between the first layer 131 and the second layer 132 is preferably less than 20, and more preferably less than 10. By configuring in this way, the flexibility of only the first layer 131 of the inner tube 130 is ensured, and the rigidity of the portion of the inner tube 130 composed of the first layer 131 and the second layer 132 is maintained. Can do. For this reason, the operativity of the balloon catheter 100 can be improved more.

  The hand operation unit 140 introduces a pressurized medium into the balloon 110 through the lumen 133 and discharges the pressurized medium to the outside through the lumen 133.

  As shown in FIG. 1, the hand operation unit 140 is connected to a proximal end portion 120 a of the outer tube 120, and introduces and discharges a pressurized medium for expanding and contracting the balloon 110. The hand operation unit 140 is connected to a syringe filled with a pressurized medium. The pressurizing medium is injected into the balloon 110 through the lumen 133 when the pusher of the syringe is pushed out toward the distal end side. On the other hand, the pressurized medium injected into the balloon 110 returns from the balloon 110 into the syringe through the lumen 133 when the syringe pusher is pulled back toward the proximal end.

  As mentioned above, according to the balloon catheter 100 which concerns on this embodiment, there exists an effect by the following structures.

  In the balloon catheter 100, the inner tube 130 includes a first layer 131, and a second layer 132 that is higher in hardness than the first layer 131 and disposed on the proximal side of the distal end of the first layer 131. I have. Therefore, the balloon catheter 100 can give flexibility to the distal end portion 131s of the inner tube 130 while sufficiently maintaining the hardness of the inner tube 130 with the simple configuration as described above.

  Further, the balloon catheter 100 does not need to be provided with a member having flexibility separate from the inner tube 130 in order to make the distal end portion 131s flexible. For this reason, the balloon catheter 100 does not need to be sufficiently fixed so that the distal end portion 131 s is not peeled off from the inner tube 130 due to stress in the living body.

  Further, in the balloon catheter 100, since the distal end portion 110b of the balloon 110 is connected to the first layer 131, the outer diameter of the distal end portion 110b of the balloon 110 is smaller than the outer diameter of the proximal end portion 110a of the balloon 110, Passability in blood vessels can be improved.

  Furthermore, since the balloon catheter 100 has a thickness t1 along the radial direction of the distal end portion 110b of the balloon 110 that is equal to or less than a thickness t2 along the radial direction of the second layer 132, the inner tube connecting the distal end portion 110b of the balloon 110 is connected. The maximum outer diameter of 130 (corresponding to the outer diameter of the second layer 132) is not increased, and introduction into the blood vessel is not hindered.

  Further, since the balloon catheter 100 connects the distal end portion 110b of the balloon 110 to the proximal end side with respect to the distal end portion 131b of the first layer 131, the inner tube 130 is sufficiently closer to the distal end side than the distal end portion 110b of the balloon 110. It can have a portion having a great flexibility. For this reason, the balloon catheter 100 can reduce the stress received when the distal end 131b of the inner tube 130 collides with the blood vessel, and can prevent peeling from the first layer 131.

  Furthermore, since the balloon catheter 100 is inclined so that the end surface 132c on the distal end side of the second layer 132 spreads radially outward from the distal end side toward the proximal end side, the distal end 131b of the inner tube 130 is placed in the blood vessel. The step is reduced by the inclined end face 132c and the portion of the second layer 132 having a larger outer diameter than the first layer 131 can be smoothly introduced without applying excessive stress to the blood vessel. .

<Modification>
Balloon catheters 200, 300, 400, and 500 according to modifications 1, 2, 3, and 4 will be described with reference to FIG.

  The balloon catheters 200, 300, 400, and 500 are different from the balloon catheter 100 according to the above-described embodiment in that a convex portion or a concave portion is formed on the inner surface of the first layer of the inner tube. With this configuration, in the balloon catheter, the contact area between the inner surface of the first layer that forms the lumen of the inner tube and the medical elongated body such as the guide wire 10 that can be inserted through the lumen of the inner tube. Can be reduced. Therefore, when a medical long body such as the guide wire 10 is inserted through the lumen of the inner tube, the sliding resistance between the inner surface of the inner tube and the medical long body can be reduced. In addition, in the modification of embodiment, the same code | symbol is added about what consists of the same structure as embodiment mentioned above, and the overlapping description is abbreviate | omitted.

  A balloon catheter 200 according to Modification 1 will be described with reference to FIG. FIG. 6A is a perspective view showing in cross section a balloon catheter 200 according to Modification 1 of the embodiment.

  The balloon catheter 200 has a first layer 231 of the inner tube 230 formed with a convex portion 231g projecting radially inward from the inner surface 231d. The convex portion 231g is formed at least in the region from the portion where the wire port portion 120f of the outer tube 120 is inserted to the end surface 231c in the first layer 231. The convex portion 231g is linearly formed in the axial direction from the proximal end side to the distal end side on the inner surface 231d of the first layer 231. A plurality of convex portions 231g are formed at a constant interval on the arc of the inner surface 231d.

  A balloon catheter 300 according to Modification 2 will be described with reference to FIG. FIG. 6B is a perspective view showing a balloon catheter 300 according to the second modification of the embodiment in cross section.

  In the balloon catheter 300, a recess 331h is formed in the first layer 331 of the inner tube 330. The recess 331h is recessed inward in the radial direction from the inner surface 331d. The recess 331h is formed in the first layer 331 at least in a region from the portion where the wire port portion 120f of the outer tube 120 is inserted to the end surface 331c. The recess 331h is linearly formed on the inner surface 331d of the first layer 331 in the axial direction from the base end side to the tip end side. A plurality of the recesses 331h are formed on the arc of the inner surface 331d with a certain interval.

  A balloon catheter 400 according to Modification 3 will be described with reference to FIG. FIG. 6C is a perspective view showing in cross section a balloon catheter 400 according to the third modification of the embodiment.

  In the balloon catheter 400, a convex portion 431i is formed on the first layer 431 of the inner tube 430 so as to protrude radially inward from the inner surface 431d thereof. The convex portion 431 i is formed at least in the region from the portion where the wire port portion 120 f of the outer tube 120 is inserted to the end surface 431 c in the first layer 431. A plurality of convex portions 431 i are formed in a matrix in a region from the base end side to the tip end side on the inner surface 431 d of the first layer 431.

  A balloon catheter 500 according to Modification 4 will be described with reference to FIG. Drawing 6 (D) is a perspective view showing the balloon catheter 500 concerning modification 4 of an embodiment in section.

  The balloon catheter 500 has a recess 531j that is recessed radially outward from the inner surface 531d of the first layer 531 of the inner tube 530. The concave portion 531j is formed at least in the region from the portion through which the wire port portion 120f of the outer tube 120 is inserted to the end surface 531c in the first layer 531. A plurality of recesses 531j are formed in a matrix in a region from the base end side to the tip end side on the inner surface 531d of the first layer 531.

  As described above, according to the balloon catheters 200, 300, 400, and 500 according to the modified examples 1, 2, 3, and 4 of the embodiment, the following effects can be obtained.

  In the balloon catheter 200, 300, 400, or 500, the first layer 131 has a convex portion (a linear convex portion 231g and a circular convex portion 431i) or a concave portion (line) on the inner surface formed in the lumen of the inner tube. At least one of a concave portion 331h and a circular concave portion 531j) is formed. Therefore, the balloon catheter 200, 300, 400, or 500 is a guide that can be inserted through the inner surface of the first layer that forms the lumen of the inner tube and the lumen of the inner tube by the convex portion or the concave portion formed in them. The contact area with the wire 10 can be reduced. Therefore, when the guide wire 10 is inserted into the lumen of the inner tube, the sliding resistance between the inner surface of the inner tube and the guide wire 10 inserted through the lumen of the inner tube is reduced, and the guide wire 10 is introduced and removed. Can be easily.

  As described above, the balloon catheter according to the present invention has been described through the embodiment and the modification. However, the present invention is not limited only to the configuration described in the embodiment and the modification, and is appropriately set based on the description of the claims. It is possible to change.

  For example, the balloon catheter according to the present invention is configured as a catheter for expanding a stenosis in a blood vessel, but is not limited to such a configuration. The balloon catheter according to the present invention includes, for example, a PTCA dilatation catheter used to widen the stenosis of the coronary artery, other blood vessels, bile ducts, trachea, esophagus, other gastrointestinal tract, urethra, otonasal lumen, other organs, etc. The present invention is applicable to catheters intended for treatment and improvement in living organs.

10 guide wire,
100, 200, 300, 400, 500 balloon catheter,
110 balloon (expansion),
110a proximal end,
110b tip,
120 outer tube,
120a proximal end,
120s tip,
120f wire port part,
130, 230, 330, 430, 530 inner pipe,
130a proximal end,
131,231,331,431 first layer,
131b, 231b, 331b, 431b, 531b tip,
131c, 231c, 331c, 431c, 531c end face (tip face),
131d, 231d, 331d, 431d, 531d inner surface,
131e lumen (for introducing the guide wire 10),
131k end face (base end face),
131s tip,
231g, 431i convex part,
331h, 531j recess,
132 second layer,
132b tip,
132c end face (tip face),
132k end face (base end face),
133 lumen (for balloon 110 expansion),
140 Hand control unit,
thickness t1 (along the radial direction of the tip 110b of the balloon 110),
t2 Thickness (along the radial direction of the second layer 132 of the inner tube 130).

Claims (6)

An extension that can be expanded and contracted by introducing and discharging a pressurized medium;
An outer tube disposed on the base end side of the extension part, to which the base end part of the extension part is connected;
An inner tube that is disposed in a lumen of the outer tube and defines a lumen through which the pressurized medium can flow between the outer tube and the distal end portion of the expansion portion is connected;
The inner tube includes a first layer and a second layer covering the first layer,
The distal end of the second layer is disposed closer to the proximal end side than the distal end of the first layer,
The first layer is a balloon catheter whose hardness is lower than that of the second layer.   The balloon catheter according to claim 1, wherein a distal end portion of the expansion portion is connected to the first layer.   The balloon catheter according to claim 2, wherein a thickness along the radial direction of the distal end portion of the expansion portion is equal to or less than a thickness along the radial direction of the second layer.   The balloon catheter according to any one of claims 1 to 3, wherein a distal end portion of the expansion portion is connected to a proximal end side with respect to a distal end of the first layer.   The balloon catheter according to any one of claims 1 to 4, wherein an end surface on the distal end side of the second layer is inclined so as to spread radially outward from the distal end side toward the proximal end side.   The balloon catheter according to any one of claims 1 to 5, wherein at least one of a convex portion and a concave portion is formed on an inner surface of the inner tube formed in the lumen of the inner tube.