JP2012157632A - Balloon catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a balloon catheter having a distal end increased in flexibility, whose balloon area has preferred rigidity.SOLUTION: The balloon catheter 10 includes an outer tube 15 and an inner tube 16. The inner tube 16 is provided to extend farther toward the distal side than the outer tube 15. This extended area is covered with a balloon 13. The inner tube 16 includes an inner proximal tube 32, an inner intermediate tube 33 continuing with the inner proximal tube 32 on the distal side, and an inner distal tube 34 continuing with the inner intermediate tube 33 on the distal side. The inner intermediate tube 33 is formed to be less rigid than the inner proximal tube 32 and more rigid than the inner distal tube 34, and lies in an area covered with a distal cone-like area 13d of the balloon 13.

Description

  The present invention relates to a balloon catheter that is used by being introduced into a living body at the time of performing an expansion treatment of a stenosis site or a blockage site of a blood vessel.

  Conventionally, balloon catheters have been used in treatments such as PTA (percutaneous angioplasty) and PTCA (percutaneous coronary angioplasty). The balloon catheter is configured by fixing a balloon to a catheter tube.

  As the balloon catheter, for example, Patent Document 1 discloses a predetermined range from the distal end portion toward the proximal side in order to increase the flexibility of the distal end portion that easily contacts a blood vessel when the catheter is inserted. A configuration in which a tip is provided is disclosed. An example of this configuration is shown in FIG.

  As shown in FIG. 7, the balloon catheter 80 includes a catheter tube 81 and a balloon 82. The catheter tube 81 includes an outer tube 83 and an inner tube 84 provided so as to penetrate the lumen of the outer tube 83, and the inner tube 84 extends to the distal end side from the outer tube 83. is set up. A balloon 82 is provided so as to cover the extended region from the outside.

  The balloon 82 is formed so that the inner diameter and the outer diameter are changed in a plurality of stages in the inflated state. Specifically, the balloon 82 includes a proximal leg region 82a joined to the outer tube 83 and a proximal cone region tapered so that the inner diameter and the outer diameter increase toward the distal end side. 82b, the straight tube region 82c having the same inner diameter and outer diameter in the entire length direction and forming the maximum outer diameter region of the balloon 82, and the inner diameter and the outer diameter are reduced toward the distal end side. Thus, the distal-side cone region 82d that is tapered and the distal-side leg region 82e joined to the inner tube 84 are provided in this order from the proximal side.

  In the above-described configuration, in the region of the inner tube 84 that is extended more distally than the outer tube 83, the region of the predetermined range from the distal end portion toward the proximal side is on the proximal side with respect to the region. The distal end tip 86 is more flexible than the continuous base tube 85. The tip chip 86 is a portion to be joined to the distal leg region 82e of the balloon 82, and is formed over a position proximal to the distal cone region 82d of the balloon 82.

  By providing the distal tip 86 as described above, the distal end portion of the catheter 80 that easily comes into contact with the blood vessel when the balloon catheter 80 is inserted into the treatment target site can be made flexible. .

JP 2008-237844 A

  Here, since the balloon 82 is formed by using blow molding or the like, the thickness of the balloon 82 is likely to be thinner on the center side than on both ends in the axial direction. Then, in a state where the deflated balloon 82 is wound around the inner tube 84, the straight tube region 82c side tends to be less rigid than the distal leg region 82e side. In this case, there is a concern about the occurrence of kinks (bending) at the change of rigidity.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to optimize the rigidity of a region where a balloon is provided in a balloon catheter having increased flexibility at a distal end.

  Hereinafter, means and the like effective for solving the above-described problems will be described while showing functions and effects as necessary.

  Balloon catheter of the first invention: A balloon catheter in which a balloon to be inflated or deflated using a fluid is provided so as to cover the distal end side of the tube body, wherein the balloon is distal to the tube body Disposed between the distal joint region that constitutes the joint portion on the side, the inflation region that constitutes the portion that projects outwardly when the balloon is inflated, and the distal joint region and the inflation region The tube body is provided on the distal side of the tube body, and on the proximal side of the distal tube, and from the distal tube. Is provided between the distal tube and the proximal tube, and is less rigid than the proximal tube and more rigid than the distal tube. Comprising an intermediate tube formed so as rigidity is increased, and the intermediate tube is characterized in that it is formed so as to be covered from the outside by at least a portion of the transition region.

  According to this configuration, in the tube body, the intermediate tube having lower rigidity than the proximal tube and higher rigidity than the distal tube exists in the region covered from the outside by the balloon transition region. As a result, even if the balloon has a configuration in which the rigidity on the inflating region side is lower than that on the distal side, the change in rigidity can be appropriately absorbed in the tube body, thereby improving passability and resistance. It becomes possible to achieve both improvement of kink properties.

  Further, the rigidity balance as described above is realized by interposing an intermediate tube different from the proximal tube and the distal tube. As a result, the above-described excellent effects can be achieved while increasing the degree of freedom in designing the tube body.

  Balloon catheter of the second invention: In the first invention, the distal end portion of the intermediate tube is present at the boundary of the transition region and the distal joint region or at a more distal side than that. It is characterized by. As a result, the intermediate tube is present in the region where the change in rigidity is likely to occur in the balloon, and the change in rigidity can be satisfactorily absorbed.

  Balloon catheter of 3rd invention: In 1st or 2nd invention, the junction location of the said intermediate | middle tube and the said distal side tube is covered from the outer side by the said distal side junction area | region. . As a result, the bonding strength between the intermediate tube and the distal tube can be supplemented by the balloon, and separation of the intermediate tube and the distal tube is suppressed.

  In particular, when this configuration is applied when the configuration according to the second aspect of the present invention is provided, for example, the junction of the intermediate tube and the distal tube on the distal side of the balloon catheter inserted into the bent blood vessel. In the configuration where there are places, it is possible to suitably increase the bonding strength of these tubes.

  Balloon catheter of 4th invention: In 3rd invention, these junction tubes of the said intermediate tube and the said distal side tube are these intermediate tubes so that the said distal side tube may produce the outer peripheral surface of the said tube body. And the distal tube is formed by laminating in the radial direction. As a result, in a configuration in which the joint portion between the intermediate tube and the distal tube is covered from the outside by the distal joint region of the balloon, a wide joint area between the distal joint region and the distal tube is ensured. Therefore, it is possible to prevent the distal tube from falling off.

  Balloon catheter of 5th invention: In invention of any one of 1st thru | or 4th invention, the proximal end part of the said intermediate | middle tube is the boundary of the said expansion | swelling area | region and the said transition area, or more than it It exists in the proximal side. Thereby, the rigidity change in the balloon can be suitably absorbed by the intermediate tube.

  In particular, when this configuration is applied when the configuration according to the second aspect of the invention is provided, an intermediate tube exists for the entire transition region in which a change in rigidity is likely to occur in the balloon. Can be suitably absorbed by the intermediate tube.

  Balloon catheter of the sixth invention: In the invention according to any one of the first to fifth inventions, a means for confirmation is provided on the tube body in order to facilitate confirmation of a predetermined position in the axial direction of the balloon. It is attached, The proximal end part of the said intermediate | middle tube exists in the distal side rather than the said confirmation means, It is characterized by the above-mentioned. This makes it possible to attach the confirmation means to the proximal tube having higher rigidity while keeping the position of the confirmation means at a desired position, and it is possible to attach the confirmation means in a stable state. .

  Balloon catheter of 7th invention: In 6th invention, the junction location of the said intermediate tube and the said proximal side tube is formed so that the said intermediate tube may become an outer side with respect to the said proximal side tube Accordingly, the confirmation means has a cylindrical shape, and the distal end surface is provided so as to abut on the step surface from the proximal side. It is characterized by being. Thereby, it becomes difficult to produce the convex part which has the surface toward the distal side in the position where the means for confirmation was attached. Therefore, it becomes difficult for the balloon to be caught by the confirmation means when the balloon catheter is inserted.

(A) It is the side view of the balloon of the inflated state which shows a balloon and an outer tube in the state of a longitudinal section, and its periphery, (a1) It is a figure which expands and shows a part about the balloon of the state of a longitudinal section, (a2 ) It is a longitudinal sectional view showing the joint portion between the inner proximal tube and the inner intermediate tube, (a3) It is a longitudinal sectional view showing the joint portion between the inner intermediate tube and the inner distal tube, and (b) the balloon is deflated. It is a side view which expands and shows the said balloon and its periphery in the case of a state. It is a schematic whole side view which shows the structure of a balloon catheter. It is a figure which shows the balloon catheter in 2nd Embodiment, Comprising: It is the side view of the balloon of the inflation state which shows a balloon and an outer tube in the state of a longitudinal cross-section, and its periphery. It is a figure which shows the balloon catheter in 3rd Embodiment, Comprising: It is the side view of the balloon of the inflation state which shows a balloon and an outer tube in the state of a longitudinal cross-section, and its periphery. It is a figure which shows the balloon catheter in 4th Embodiment, Comprising: It is the side view of the balloon of the expansion | swelling state which shows a balloon and an outer tube in the state of a longitudinal section, and its periphery. It is a figure which shows the balloon catheter in 5th Embodiment, Comprising: It is the side view of the balloon of the inflation state which shows a balloon and an outer tube in the state of a longitudinal cross-section, and its periphery. It is a figure for demonstrating background art, Comprising: It is a side view of the balloon of the expansion | swelling state which shows a balloon and an outer tube in the state of a longitudinal cross-section, and its periphery.

(First embodiment)
Hereinafter, a first embodiment of a balloon catheter will be described with reference to the drawings. First, a schematic configuration of the balloon catheter 10 will be described with reference to FIG. FIG. 2 is a schematic overall side view showing the configuration of the balloon catheter 10.

  As shown in FIG. 2, the balloon catheter 10 includes a catheter tube 11, a hub 12 attached to the proximal end (base end) of the catheter tube 11, and a distal end side (tip side) of the catheter tube 11. ) Attached to the balloon 13. The length of the balloon catheter 10 is 1 m to 2 m.

  The catheter tube 11 is composed of a plurality of tubes, and has an inner and outer multiple tube structure from at least a midway position in the axial direction (longitudinal direction) to the position of the balloon 13. Specifically, the catheter tube 11 includes an outer tube 15 and an inner tube 16 having a diameter smaller than that of the outer tube 15, and the inner tube 16 is inserted into the outer tube 15. It has an inner and outer double pipe structure. The inner tube 16 corresponds to a tube body.

  The outer tube 15 is formed in a tubular shape having outer tube holes 21 (see FIG. 1) which are continuous over the entire axial direction and open at both ends. In addition, the outer tube 15 is an outer proximal tube 22 in which a region within a predetermined range from a position continuous to the hub 12 toward the distal side is formed of a metal such as a Ni—Ti alloy or stainless steel. However, the distal side is an outer distal tube 23 formed of thermoplastic polyamide so that the rigidity is lower than that of the outer proximal tube 22.

  In addition, you may form the outer side proximal tube 22 with a synthetic resin. In this specification, the term “rigidity” refers to the magnitude of a moment that acts when the catheter is bent in a direction perpendicular to the axial direction.

  The inner tube 16 is formed in a tubular shape having inner tube holes 31 (see FIG. 1) that are continuous over the entire axial direction and open at both ends. Further, the proximal end of the inner tube 16 is joined to an intermediate position in the axial direction of the outer distal tube 23, and further extends further to the distal side than the outer tube 15, as shown in FIG. Is provided. A balloon 13 is provided so as to cover the extended region from the outside.

  The outer tube hole 21 functions as a fluid lumen through which the compressed fluid flows when the balloon 13 is inflated or deflated. The inner tube hole 31 functions as a wire lumen through which a guide wire G used when the balloon catheter 10 is inserted into the living body is inserted.

  Next, the configuration of the balloon 13 and the inner tube 16 will be described in detail with reference to FIG.

  FIG. 1A is a side view showing the balloon 13 and its surroundings when the balloon 13 is in an inflated state. In FIG. 1A, the balloon 13 and the outer tube 15 are shown in a vertical cross-sectional state. 1 (a1) is an enlarged view of a part of the balloon 13 in a longitudinal section, and FIG. 1 (a2) is an enlarged longitudinal sectional view of a part of the inner tube 16. FIG. 1A3 is a longitudinal sectional view showing a part of the balloon 13 and the inner tube 16 in an enlarged manner. FIG. 1B is a side view showing the balloon 13 and its surroundings when the balloon 13 is in a deflated state.

  The balloon 13 is made of a thermoplastic polyamide elastomer. However, it is not limited to this, and is formed of other synthetic resins such as polyolefin, polyolefin elastomer, polyester, polyester elastomer, polyamide, polyimide, polyimide elastomer, polyurethane, polyurethane elastomer, polyethylene terephthalate, silicon rubber, styrene olefin rubber, etc. May be. Moreover, you may form with the material which mixed 2 or more types among the synthetic resin enumerated in this way, and the said polyamide elastomer, In this case, it may be a single layer structure and may be a multilayer structure.

  The production method of the balloon 13 is not particularly limited, and examples thereof include a production method by blow molding, dipping molding, extrusion molding, and the like. However, in the case of dilatation treatment of a stenosis occurring in the coronary artery of the heart, it is preferable that the balloon 13 has a sufficient pressure resistance, and in this case, blow molding is preferable.

  An example of a method for manufacturing the balloon 13 by the blow molding is as follows. First, the tubular parison which becomes the origin of the balloon 13 is produced by extrusion molding. Next, the tubular parison is stretched in the length direction, and then blow-molded under predetermined conditions using a mold in which a mold corresponding to the shape of the balloon 13 is formed. Thereby, the tubular parison is in a state of being biaxially stretched. Then, the manufacture of the balloon 13 is completed by cutting both ends of the stretched tubular parison. The blow molding may be performed under room temperature conditions or under heating conditions. Further, the blow molding may be performed a plurality of times. Furthermore, the stretching in the axial direction and the stretching in the radial direction may be performed simultaneously. Further, annealing may be performed after biaxial stretching.

  As shown in FIG. 1A, the balloon 13 is formed so that the inner diameter and the outer diameter are changed in a plurality of stages in the inflated state. That is, the balloon 13 has a proximal leg region (proximal side joining region) 13a joined to the outer tube 15 and a proximal shape tapered so that the inner diameter and the outer diameter are increased toward the tip side. A side cone region (proximal transition region) 13b, a straight tube region (expansion region) 13c having the same inner diameter and outer diameter throughout the length direction and forming the maximum outer diameter region of the balloon 13, A distal cone region (distal transition region) 13d that is tapered so that the inner diameter and the outer diameter are reduced toward the distal end side, and a distal leg region (distant region) joined to the inner tube 16 The distal side joining region) 13e in this order from the proximal side.

  The length of the proximal leg region 13a in the axial direction is 0.5 mm to 5.0 mm, and the length of the proximal cone region 13b in the axial direction is 0.5 mm to 5.0 mm. The axial length of the region 13c is 10 mm to 50 mm, the axial length of the distal cone region 13d is 0.5 mm to 10.0 mm, and the axial length of the distal leg region 13e is The length dimension is 0.5 mm to 2.0 mm. Further, the outer diameter of the straight tube region 13c when the balloon 13 is inflated is 1.0 mm to 5.0 mm, and is straight when the balloon 13 is contracted before being inflated (that is, the balloon 13 is folded). The outer diameter of the tube region 13c is 0.5 mm to 1.5 mm.

  In this case, the axial length of the distal cone region 13d is larger than the axial length of the proximal cone region 13b, and the axial length of the distal cone region 13d. The dimension is preferably substantially the same as the length dimension of the straight pipe region 13c in the axial direction. Thereby, the ratio of the distal cone region 13d to the entire length of the balloon 13 can be increased, and the inclination of the distal cone region 13d can be made as gentle as possible. Therefore, as shown in FIG. 1B, the balloon 13 is deflated, and the proximal cone region 13b, the straight tube region 13c, and the distal cone region 13d of the balloon 13 are wound around the outer peripheral surface of the inner tube 16. In the state, the change of the outer diameter becomes gentle in the portion from the distal end side to the straight tube region 13c, and the passage property when the balloon catheter 10 is inserted into the body is improved.

  In the configuration in which the balloon 13 is formed by a plurality of wings (for example, three wings), when the balloon 13 is contracted, each wing is individually wrapped around the inner tube 16. Specifically, when the balloon 13 changes from the inflated state to the deflated state, the balloon 13 is inflated and deflated (proximal cone region 13b) so that a plurality of wings standing perpendicular to the axial direction are formed at equal intervals. The straight tube region 13c and the distal cone region 13d) are folded, and then each wing wraps around the inner tube 16 and enters a contracted state.

  The inner tube 16 is formed by connecting a plurality of tubes 32 to 34 side by side so as to be on the same axis. Specifically, an inner proximal tube 32 that configures from the proximal end of the inner tube 16 to a middle position on the distal side of the outer tube 15, and a distal side with respect to the inner proximal tube 32. A continuous inner intermediate tube 33 and an inner distal tube 34 that is continuous with the inner intermediate tube 33 on the distal side and that forms the distal end of the inner tube 16 are provided. The inner proximal tube 32 corresponds to the proximal tube, the inner intermediate tube 33 corresponds to the intermediate tube, and the inner distal tube 34 corresponds to the distal tube.

  The inner proximal tube 32 is formed of a synthetic resin, and specifically has a three-layer structure in which a plurality of types of synthetic resins are laminated. Specifically, the outer layer is formed of a thermoplastic polyamide elastomer equivalent to a Shore hardness of 70D, the intermediate layer is formed of low-density polyethylene, and the inner layer is formed of high-density polyethylene. In FIG. 1 (a2), the inner proximal tube 32 is shown as a single layer for convenience of explanation.

  The inner intermediate tube 33 is made of a synthetic resin and has a single layer structure. The inner intermediate tube 33 is formed using a resin material having a Shore hardness smaller than that of the thermoplastic polyamide elastomer used in the inner proximal tube 32. Specifically, it is formed of a thermoplastic polyamide elastomer having a Shore hardness smaller than that of the thermoplastic polyamide elastomer used in the inner proximal tube 32, specifically, a polyamide elastomer equivalent to a Shore hardness of 63D.

  The inner distal tube 34 is made of a synthetic resin and has a single layer structure. The inner distal tube 34 is formed using a resin material having a Shore hardness smaller than that of the thermoplastic polyamide elastomer used in the inner intermediate tube 33. Specifically, a thermoplastic polyamide elastomer having a Shore hardness smaller than that of the thermoplastic polyamide elastomer used in the inner intermediate tube 33, specifically, a polyamide elastomer equivalent to a 55D Shore hardness and a polyamide elastomer equivalent to 63D. It is made of a material mixed at a ratio of 1: 1.

  A joint 35 (hereinafter also referred to as a first joint 35) between the inner proximal tube 32 and the inner intermediate tube 33 is predetermined in the axial direction in the straight tube region 13c of the balloon 13, as shown in FIG. It exists at a position corresponding to the position, specifically the intermediate position. As shown in FIG. 1 (a2), the first joint 35 expands the proximal end opening of the inner intermediate tube 33, and the distal end portion of the inner proximal tube 32 is inserted into the expanded region. And the insertion location is heated from the outside and both the tubes 32 and 33 are heat-welded and formed. In this case, the inner intermediate tube 33 is laminated on the inner proximal tube 32 from the outside at the first joint 35, and the region laminated outside the inner intermediate tube 33 is the inner proximal tube. The tube 32 protrudes outward from the outer peripheral surface. On the other hand, when forming the first joint portion 35, heat welding is performed with the mandrel inserted into the inner tube hole 31, so that the inner diameter of the inner tube 16 including the first joint portion 35 is the same or substantially the same. It has become. Note that the bonding method is not limited to heat welding, and an adhesive may be used.

  In order to improve the visibility of the balloon 13 under X-ray projection and to easily position the balloon 13 to the target treatment site, the first joint portion 35 is made of metal and is a cylinder. A contrast ring (contrast marker) 36 is provided. The contrast ring 36 is formed of stainless steel, but is not limited thereto, and gold, platinum, iridium, cobalt chromium alloy, titanium, or the like may be used. The contrast ring 36 corresponds to the confirmation means.

  The contrast ring 36 is disposed such that the distal end surface 36a abuts on a stepped surface 33a generated so as to face the proximal side at the first joint 35. That is, the contrast ring 36 is attached to the inner proximal tube 32 having high rigidity among the inner proximal tube 32 and the inner intermediate tube 33. Thereby, it becomes possible to support the contrast ring 36 stably.

  The step surface 33a generated so as to face the proximal side is not limited to a plane that is perpendicular to the axial direction, and may be a plane that forms an acute angle or an obtuse angle with respect to the axial direction, for example. It may be a curved surface that is convex on the proximal side or recessed on the distal side.

  The method of attaching the contrast ring 36 is arbitrary, but in the present balloon catheter 10, the contrast ring 36 is attached by caulking. Briefly describing this attachment method, a contrast ring 36 having an inner diameter slightly larger than the outer diameter of the tube to be attached is inserted and arranged on the tube to be attached, and then an external force is applied to the outer peripheral surface of the contrast ring 36. In addition, the contrast ring 36 is deformed and the contrast ring 36 is pressure-bonded to the tube. Thus, when the contrast ring 36 is attached, the attachment work can be suitably performed by setting the tube to be attached to the inner proximal tube 32 having high rigidity in the inner tube 16.

  The outer diameter of the contrast ring 36 is the same as or substantially the same as the outer diameter of the first joint portion 35. Thereby, it is possible to prevent a metal protrusion having a surface facing the distal side from being generated in the region covered with the balloon 13 in the inner tube 16. In order not to generate such a protrusion, the outer diameter of the contrast ring 36 may be set to be equal to or smaller than the outer diameter of the first joint portion 35.

  A joint 37 (hereinafter also referred to as a second joint 37) between the inner intermediate tube 33 and the inner distal tube 34 corresponds to the distal leg region 13e of the balloon 13 as shown in FIG. Exists in position. That is, the second joint location 37 exists in the joint region on the distal side of the balloon 13 with respect to the inner tube 16.

  In detail, as shown in FIG. 1 (a3), the distal end portion of the inner intermediate tube 33 is inserted into the proximal end opening side of the inner distal tube 34, and the insertion portion is moved outward. It is formed by heating and heat-welding both tubes 33 and 34. This thermal welding is performed in a state where the mandrel is inserted so that the inner diameter of the inner tube 16 including the second joint portion 37 is the same or substantially the same, and the second joint portion 37 does not have a step and the first step is not performed. 2 It is performed by heat-compressing from the outside using a heat shrinkable tube or the like so that the outer peripheral surface is flush with the joint portion 37 and its periphery. Thereby, the outer peripheral surface of the inner tube 16 is flush with the second joint location 37 and the periphery thereof, and the inner distal tube 34 generates the outer peripheral surface of the inner tube 16 at the second joint location 37. Note that the bonding method is not limited to heat welding, and an adhesive may be used.

  Further, when the balloon 13 is joined to the inner tube 16, the distal leg region 13e is arranged so as to cover the second joining portion 37 formed as described above from the outside, and the distal leg region By heating from the outside of 13e, the entire distal leg region 13e is thermally welded to the inner tube 16. Therefore, the balloon 13 is bonded to the inner intermediate tube 33, bonded to the inner distal tube 34, and further bonded to the second bonding point 37.

  As described above, since the second joint portion 37 overlaps the joint region on the distal side of the balloon 13, the joint strength of the second joint portion 37 can be supplemented by the balloon 13. Therefore, separation between the inner intermediate tube 33 and the inner distal tube 34 is suppressed. Further, as described above, the inner distal tube 34 is laminated from the outer side on the inner intermediate tube 33 at the second joint 37, and the inner distal tube 34 covers the outer peripheral surface of the inner tube 16. Therefore, the bonding area of the balloon 13 with respect to the inner distal tube 34 is secured widely. Therefore, it is possible to suppress the inner distal tube 34 from falling off. Furthermore, by covering the second joint portion 37 with the balloon 13, the outer shape of the balloon catheter 10 on the distal end side can be made smooth without being affected by the shape of the second joint portion 37. It becomes.

  The outer diameter of the inner tube 16 is basically constant except for the first joint portion 35. Further, the inner diameter of the inner tube 16 is generally constant. Incidentally, the outer diameter of the fixed part is 0.50 mm to 0.60 mm, and the inner diameter is 0.40 mm to 0.48 mm.

  In such a configuration in which the outer diameter and the inner diameter are basically constant, as described above, the inner intermediate tube 33 is formed of a material having a Shore hardness smaller than that of the inner proximal tube 32, and the inner distal tube. The tube 34 is formed of a material having a Shore hardness smaller than that of the inner intermediate tube 33. Therefore, the inner tube 16 is gradually reduced in rigidity toward the distal side. That is, the inner intermediate tube 33 is set to be lower in rigidity than the inner proximal tube 32, and the inner distal tube 34 is set to be lower in rigidity than the inner intermediate tube 33. Thereby, the passability and kink resistance (resistance against bending) can be improved.

  Here, in the configuration in which the distal side of the inner tube 16 is lower in rigidity than the proximal side, the inner tube 16 is interposed between the inner proximal tube 32 and the inner distal tube 34 than the inner proximal tube 32. Also, the inner intermediate tube 33 having a lower rigidity and higher rigidity than the inner distal tube 34 is positively provided.

  As shown in FIG. 1 (a), the inner intermediate tube 33 is located more proximal than the position corresponding to the boundary between the straight tube region 13c and the distal cone region 13d of the balloon 13, more specifically, the straight tube. From a position corresponding to the middle position of the region 13c, a position more distal than the position corresponding to the boundary between the distal cone region 13d and the distal leg region 13e of the balloon 13, more specifically, the distal leg region 13e. It exists over the position corresponding to the halfway position.

  As shown in FIG. 1 (a1), the balloon 13 is generally formed so that its thickness gradually decreases from both ends in the axial direction toward the straight tube region 13c. This tendency becomes remarkable when the balloon 13 is formed by the blow molding described above. If it does so, when it sees with the balloon 13 single-piece | unit, the direction of the straight pipe | tube area | region 13c side will become low compared with the distal end side. In this case, if it is assumed that the inner distal tube 34 exists in the range of the balloon 13, the influence of the change in rigidity of the balloon 13 cannot be absorbed on the inner tube 16 side, and the occurrence of kinks is caused. Concerned. On the other hand, if the inner proximal tube 32 is extended to the region where the rigidity changes as described above, there is a concern that the passage of the balloon catheter 10 is deteriorated. On the other hand, the presence of the inner intermediate tube 33 as described above prevents the passage of the balloon catheter 10 from being lowered while absorbing the influence of the rigidity change of the balloon 13 in the inner tube 16. It becomes possible.

  With respect to the passage of the balloon catheter 10, the inner distal tube 34 is formed in a tapered shape by tapering the region distal to the balloon 13 with a constant inner diameter, as shown in FIG. ing. In addition, the dimension of the range extended in the distal side rather than the balloon 13 in the inner side distal tube 34 is 2.0 mm-5.0 mm.

  Further, as shown in FIG. 1 (a3), the distal leg region 13e is also tapered by being tapered while keeping the inner diameter constant. Thereby, it becomes possible to produce a generally continuous taper shape from the distal end portion of the inner tube 16 to the distal leg region 13e, and the passage of the balloon catheter 10 can be improved. In this case, as already described, the second joint location 37 and its periphery are formed to be flush with each other. Therefore, in the configuration in which the distal leg region 13e is provided so as to cover the second joint location 37, it is possible to satisfactorily form the tapered shape of the distal leg region 13e.

  In FIG. 1 (a3), the non-tapered portion is interposed between the distal leg region 13e and the tapered portion of the inner distal tube 34 so that the tapered portion is intermittently present. However, the non-tapered portion may not be interposed, and the tapered portion may be continuous. The tapered shape is formed by polishing, for example.

  Furthermore, as shown in FIG. 1B, in the contracted state of the balloon 13, the taper shape to be tapered exists over the distal cone region 13d of the balloon 13. Thereby, it is possible to further improve the passability of the balloon catheter 10.

  Next, a method for using the balloon catheter 10 will be briefly described.

  First, a guiding catheter is inserted into a sheath introducer inserted into a blood vessel, and is introduced to the coronary artery entrance by pushing and pulling. Next, the guide wire G is inserted through the inner lumen 31 of the balloon catheter 10 and introduced from the coronary artery entrance to the peripheral site through the stenosis. Subsequently, the balloon catheter 10 is inserted along the guide wire G to the stenosis site while performing a push-pull operation. In this case, as already described, not only the inner distal tube 34 but also the inner intermediate tube 33 is provided, so that the straight tube region 13c and the distal side of the balloon 13 are improved while improving the passage of the balloon catheter 10. It is possible to suppress the occurrence of kinks at the location where the cone region 13d is provided.

  Thereafter, a pressurized fluid is injected into the balloon 13 from the hub 12 side to inflate the balloon 13 to expand the occlusion site or the stenosis site. Thereafter, the compressed fluid injected into the balloon 13 is extracted to contract the balloon 13, and the balloon catheter 10 is extracted from the body.

  The balloon catheter 10 is mainly passed through a blood vessel as described above and used for treating blood vessels such as coronary arteries, femoral arteries, and pulmonary arteries. It can also be applied to “tubes” and “body cavities”.

  According to the embodiment described in detail above, the following excellent effects are obtained.

  An inner intermediate tube 33 having lower rigidity than the inner proximal tube 32 and higher rigidity than the inner distal tube 34 is provided at a position corresponding to the range from the distal cone region 13d to the straight tube region 13c in the balloon 13. It has been. Thereby, even if the straight tube region 13c side of the balloon 13 is configured to have lower rigidity than the distal side, the change in rigidity can be appropriately absorbed by the inner tube 16, and the passage property can be improved. It is possible to achieve both improvement and improvement of kink resistance.

  Further, the balance of rigidity as described above is realized by interposing an inner intermediate tube 33 different from the inner proximal tube 32 and the inner distal tube 34. Thereby, the above excellent effects can be obtained while increasing the degree of freedom in designing the inner tube 16.

  Further, the position of the proximal end portion of the inner intermediate tube 33 is more distal than the contrast ring 36, and the contrast ring 36 is attached to the inner proximal tube 32. By attaching the contrast ring 36 to the inner distal tube 34 having relatively high rigidity in this way, the contrast ring 36 can be attached in a stable state.

  Further, a second joint portion 37 that is a joint portion between the inner intermediate tube 33 and the inner distal tube 34 is covered with the distal leg region 13 e of the balloon 13. Thereby, it becomes possible to supplement the joint strength of the second joint location 37 on the balloon 13 side, and the separation between the inner intermediate tube 33 and the inner distal tube 34 is suppressed.

(Second Embodiment)
FIG. 3 is a schematic overall side view showing the configuration of the balloon catheter 40 according to the second embodiment. In FIG. 3, the same components as those in the first embodiment are denoted by the same reference numerals, and the description of the components is basically omitted in the following description.

  As shown in FIG. 3, the inner tube 16 of the balloon catheter 40 also includes an inner intermediate tube 33 formed so as to be less rigid than the inner proximal tube 32 and higher than the inner distal tube 34. ing. The position of the distal end portion of the inner intermediate tube 33 is a position overlapping the distal leg region 13e of the balloon 13 in the same manner as the balloon catheter 10. On the other hand, the position of the proximal end portion of the inner intermediate tube 33 is more distal than the boundary between the straight tube region 13 c and the distal cone region 13 d in the balloon 13. However, this position is closer to the boundary between the straight tube region 13c and the distal cone region 13d.

  In this configuration, since the inner proximal tube 32 extends distally than the balloon catheter 10, the rigidity is increased accordingly, but the change in the rigidity of the balloon 13 can be absorbed well by that amount. It becomes.

(Third embodiment)
FIG. 4 is a schematic overall side view showing the configuration of the balloon catheter 50 according to the third embodiment. In FIG. 4, the same components as those in the first embodiment are denoted by the same reference numerals, and the description of the components is basically omitted in the following description.

  As shown in FIG. 4, the inner tube 16 of the present balloon catheter 50 also includes an inner intermediate tube 33 formed so as to be less rigid than the inner proximal tube 32 and higher than the inner distal tube 34. ing. The position of the proximal end portion of the inner intermediate tube 33 is an intermediate position in the axial direction in the straight tube region 13 c of the balloon 13, similarly to the balloon catheter 10. On the other hand, the position of the distal end portion of the inner intermediate tube 33 is closer to the proximal side than the distal leg region 13 e of the balloon 13. However, this position is a position corresponding to an intermediate position in the axial direction in the distal cone region 13d of the balloon 13, and more specifically, near the boundary between the distal cone region 13d and the distal leg region 13e. Is in position.

  In this configuration, the inner distal tube 34 enters the distal cone region 13d from the distal side, but most of the distal cone region 13d exists at a position corresponding to the inner intermediate tube 33. Therefore, it is possible to absorb the rigidity change in the balloon 13.

  Moreover, according to this structure, the junction location of the balloon 13 with respect to the inner tube 16 and the junction location of the inner intermediate tube 33 and the inner distal tube 34 are separated in the axial direction. As a result, it is possible to disperse joint portions where rigidity is likely to increase in the axial direction.

(Fourth embodiment)
FIG. 5 is a schematic overall side view showing the configuration of the balloon catheter 60 in the fourth embodiment. In FIG. 5, the same components as those in the first embodiment are denoted by the same reference numerals, and the description of the components is basically omitted in the following description.

  As shown in FIG. 5, the inner tube 16 of the balloon catheter 60 also includes an inner intermediate tube 33 formed so as to be less rigid than the inner proximal tube 32 and higher than the inner distal tube 34. ing. The position of the proximal end portion of the inner intermediate tube 33 is an intermediate position in the axial direction in the straight tube region 13 c of the balloon 13, similarly to the balloon catheter 10. On the other hand, the position of the distal end portion of the inner intermediate tube 33 is more distal than the distal leg region 13 e of the balloon 13. However, this position is closer to the distal leg region 13e.

  In this configuration, the inner intermediate tube 33 exists for the entire region where the thickness of the balloon 13 on the distal side of the straight tube region 13c can change. Thereby, the rigidity change of the balloon 13 can be absorbed by the inner intermediate tube 33.

  Moreover, according to this structure, the junction location of the balloon 13 with respect to the inner tube 16 and the junction location of the inner intermediate tube 33 and the inner distal tube 34 are separated in the axial direction. As a result, it is possible to disperse joint portions where rigidity is likely to increase in the axial direction.

(Fifth embodiment)
FIG. 6 is a schematic overall side view showing the configuration of the balloon catheter 70 according to the fifth embodiment. In FIG. 6, the same components as those in the first embodiment are denoted by the same reference numerals, and the description of the components is basically omitted in the following description.

  As shown in FIG. 6, the inner tube 16 of the present balloon catheter 70 also includes an inner intermediate tube 33 formed so as to be less rigid than the inner proximal tube 32 and higher than the inner distal tube 34. ing. The position of the proximal end of the inner intermediate tube 33 is more proximal than the distal end of the outer tube 15, and the position of the distal end of the inner intermediate tube 33 is the distal side of the balloon 13. It is on the distal side of the leg region 13e. Incidentally, the contrast ring 36 is attached to the inner intermediate tube 33.

  In this configuration, the inner intermediate tube 33 exists for the entire balloon 13. Thereby, the rigidity change of the balloon 13 can be absorbed by the inner intermediate tube 33. In addition, the flexibility of the region where the balloon 13 is provided in the balloon catheter 10 can be made higher than that of the balloon catheter 10.

  In this balloon catheter 70, the position of the distal end portion of the inner intermediate tube 33 may be a position like the balloon catheter 40 in the second embodiment, and the balloon catheter 50 in the third embodiment. It is good also as a position like this.

(Other embodiments)
The present invention is not limited to the description of the above embodiment, and may be implemented as follows, for example.

  (1) The forming material of the inner proximal tube 32, the inner intermediate tube 33, and the inner distal tube 34 is less rigid than the inner proximal tube 32 and more rigid than the inner distal tube 34. If it is high, it is optional.

  (1-1) The inner proximal tube 32 is made of a synthetic resin such as polyethylene, polyethylene terephthalate, polypropylene, polyurethane, polyamide, polyamide elastomer, polyimide, polyimide elastomer, silicon rubber, etc. It may be formed as a multilayer structure. Moreover, it is good also as a single layer structure not using a multilayer structure but using the synthetic resin enumerated as mentioned above. In this case, it may be formed of one kind of synthetic resin or may be formed of a material in which two or more kinds are mixed.

  (1-2) The inner intermediate tube 33 and the inner distal tube 34 may be independently formed using a synthetic resin such as polyethylene, polyethylene terephthalate, polypropylene, polyurethane, polyamide, polyimide, polyimide elastomer, silicon rubber, or the like. Good. In this case, a single layer structure may be used as in the above embodiment, and the single layer structure may be formed of one kind of synthetic resin, or may be formed of a material in which two or more kinds are mixed. . Moreover, it is good also as a multilayer structure using the synthetic resin enumerated as mentioned above.

  As the multilayer structure, like the inner proximal tube 32 in the above embodiment, the outer layer is formed of polyamide elastomer, the intermediate layer is formed of low density polyethylene, and the inner layer is formed of high density polyethylene. It is good also as composition which has. When this configuration is applied to the above embodiment, the inner proximal tube 32, the inner intermediate tube 33, and the inner distal tube 34 have the same multilayer structure, but a synthetic resin (specifically, a polyamide elastomer) that produces an outer layer. ) Of the inner proximal tube 32> the inner intermediate tube 33> the inner distal tube 34, the inner intermediate tube 33 is less rigid than the inner proximal tube 32 and the inner distal tube 34. It becomes possible to set it as a higher structure.

  (2) Even if the 1st junction location 35 is formed based on expanding the distal end part of the inner proximal tube 32, and inserting the inner intermediate tube 33 in the expanded area. Good. Even if it is the said structure, it is good also as a structure which attaches the contrast ring 36 to the inner side proximal tube 32, and it is good also as a structure attached to the inner side intermediate tube 33 instead of this. In the latter case, the proximal end surface of the contrast ring 36 is applied from the distal side to the proximal side surface (distal end surface of the inner proximal tube 32) generated at the first joint 35. It is good also as a structure to touch. Moreover, you may form the 1st junction location 35 so that an outer peripheral surface may become flush | level with respect to a periphery similarly to 2nd junction locations 37, such as the said 1st Embodiment.

  (3) The 2nd junction location 37 is good also as a structure formed based on expanding the diameter of the proximal end part of the inner side distal tube 34, and inserting the inner side intermediate tube 33 in the diameter-expanded area | region. . Moreover, it is good also as a structure formed based on inserting the inner side distal tube 34 in the area | region which expanded the diameter of the distal end part of the inner side intermediate tube 33, and expanded the diameter. In this case, the second joining portion 37 has a shape protruding outward from the periphery thereof, but by covering the shape with the distal leg region 13e of the balloon 13, the shape is changed to the distal leg region 13e. Thus, the outer shape of the balloon catheter 10 on the distal end side can be made smooth.

  (4) The inner tube 16 may be formed so as to have a constant outer diameter including the first joint portion 35 and the second joint portion 37. Moreover, in addition to or instead of the configuration in which the tapered region in the inner tube 16 exists from the midway position in the axial direction of the inner distal tube 34 to the distal end portion, the tapered region is the inner proximal tube. 32 and at least one of the inner intermediate tube 33, the inner intermediate tube 33, the inner intermediate tube 33, or the inner distal tube 34. It may exist over the place tube 34.

  (5) The distal end portion of the inner intermediate tube 33 may be present at the boundary between the distal cone region 13d and the distal leg region 13e, and the proximal end portion of the inner intermediate tube 33 is a straight tube region. It may exist at the boundary between 13c and the distal cone region 13d.

  (6) The inner tube 16 is not limited to the configuration formed by the three tubes 32 to 34, and may be formed by four tubes or five or more tubes. For example, a tube having the same rigidity as the inner intermediate tube 33, a tube having the same rigidity as the inner distal tube 34, or an inner intermediate tube between the inner intermediate tube 33 and the inner distal tube 34 in the above embodiments. A configuration may be adopted in which a tube having lower rigidity than 33 and higher rigidity than the inner distal tube 34 is interposed. Further, between the inner proximal tube 32 and the inner intermediate tube 33 in each of the above embodiments, a tube having the same rigidity as the inner proximal tube 32, a tube having the same rigidity as the inner intermediate tube 33, or an inner proximal There may be a configuration in which a tube having lower rigidity than the tube 32 and higher rigidity than the inner intermediate tube 33 exists.

  (7) In order to increase the strength of the distal end opening of the inner distal tube 34, the material forming the distal end of the inner distal tube 34 is more rigid than the region where the proximal end is continuous. It is good also as a structure which makes it a material or embeds reinforcement members, such as a metal ring, in the distal end part of the inner distal tube 34.

  (8) The confirmation means attached to the first joint portion 35 is not limited to the contrast ring 36, and may be a visual ring having a cylindrical shape.

  (9) The inner tube 16 is not limited to the structure forming the wire lumen, and the inner tube 16 may form the fluid lumen. In this case, the distal end of the inner tube 16 is closed, and instead, a through-hole penetrating inward and outward is formed in a region of the inner tube 16 covered with the balloon 13. Even in this configuration, the inner tube 16 preferably includes at least the inner proximal tube 32, the inner intermediate tube 33, and the inner distal tube 34. In this configuration, it is preferable that the wire lumen is formed by a tube different from the inner tube 16, and the outer tube 15 is not provided and the inner tube 16 has the function of the outer tube 15. Also good.

  DESCRIPTION OF SYMBOLS 10 ... Balloon catheter, 13 ... Balloon, 15 ... Outer tube, 16 ... Inner tube, 32 ... Inner proximal tube, 33 ... Inner intermediate tube, 34 ... Inner distal tube, 35 ... First joint, 36 ... Contrast ring , 37 ... second joint location, 40, 50, 60, 70 ... balloon catheter.

Claims (7)

In a balloon catheter in which a balloon that is inflated or deflated using a fluid is provided so as to cover the distal end side of the tube body,
The balloon is
A distal joint region constituting a distal joint with respect to the tube body;
An inflatable region constituting a portion projecting outwardly when the balloon is inflated;
A transition region provided between the distal junction region and the inflation region;
With
The tube body is
A distal tube constituting the distal side of the tube body;
A proximal tube provided proximal to the distal tube and configured to be more rigid than the distal tube;
An intermediate tube provided between the distal and proximal tubes and formed to be less rigid than the proximal tube and more rigid than the distal tube;
With
The balloon catheter, wherein the intermediate tube is formed so that at least a part thereof is covered from the outside by the transition region.   2. The balloon catheter according to claim 1, wherein a distal end portion of the intermediate tube is present at a boundary between the transition region and the distal side joining region or at a more distal side than the boundary.   The balloon catheter according to claim 1 or 2, wherein a joint portion between the intermediate tube and the distal tube is covered from the outside by the distal joint region.   The junction between the intermediate tube and the distal tube is formed by laminating the intermediate tube and the distal tube in the radial direction so that the distal tube generates the outer peripheral surface of the tube body. The balloon catheter according to claim 3.   The proximal end portion of the intermediate tube exists at a boundary between the expansion region and the transition region or on a more proximal side than the boundary. Balloon catheter. A confirmation means is attached to the tube body in order to facilitate confirmation of a predetermined position in the axial direction of the balloon,
The balloon catheter according to any one of claims 1 to 5, wherein a proximal end portion of the intermediate tube exists on a distal side of the confirmation means. The junction between the intermediate tube and the proximal tube has a stepped surface directed toward the proximal side by forming the intermediate tube to be outside the proximal tube. And
The balloon catheter according to claim 6, wherein the confirmation means has a cylindrical shape and is provided such that a distal end surface thereof is in contact with the stepped surface from the proximal side.

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