JP2008200317A - Balloon catheter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the constitution in a region in which a balloon is installed and its peripheral region, and to improve the operability of a balloon catheter. <P>SOLUTION: This balloon catheter 10 is equipped with a distal shaft 13, an inner shaft 14, a balloon 16, and a distal end chip body 18. Both of the shafts 13 and 14 are tubular, and in addition, the inner shaft 14 is fitted in the distal shaft 13. The inner shaft 14 is installed in a manner to be extended closer to the distal end than to the distal shaft 13, and the distal end chip body 18 is bonded to the distal end section. Also, the proximal end side of the balloon 16 is bonded to the distal end section of the distal shaft 13. Then, the distal end side of the balloon 16 is installed by being bonded to the proximal end section of the distal end chip body 18. In this constitution, on the extended region 36 of the inner shaft 14, a step section 37 is formed so that the distal end side may have a smaller diameter. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a balloon catheter that is used by being inserted into a living body in the case 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 PTCA (percutaneous coronary angioplasty). For example, as shown in Patent Literature 1 and Patent Literature 2, a general balloon catheter is configured by joining a balloon that can be inflated and deflated by adjusting internal pressure to the distal end portion of a catheter shaft. Specifically, the catheter shaft includes an outer shaft and an inner shaft provided so as to penetrate the lumen of the outer shaft, and the inner shaft is installed so as to extend toward the distal end side than the outer shaft. A balloon is provided with the distal end side and the proximal end side held with respect to the extended portion of the inner shaft and the distal end portion of the outer shaft, respectively. The compressed fluid that inflates and compresses the balloon is circulated through the lumen of the outer shaft. In addition, a guide wire is inserted through the lumen of the inner shaft during insertion into the patient's artery.

When PTCA is performed using a balloon catheter, a guiding catheter is first inserted from the femoral artery, the tip is placed at the entrance of the coronary artery via the aorta, and then the guide wire is constricted or occluded. Pass through. Then, a balloon catheter is inserted along the guide wire so that the balloon coincides with the stenosis site or the occlusion site, and a compressed fluid is supplied to the balloon to inflate the balloon to perform dilatation treatment. After this expansion treatment, the balloon is decompressed and deflated, and the balloon catheter is removed from the body.
JP 2002-253678 A JP-A-11-33122

  Here, as performance required for the balloon catheter, for example, as disclosed in Patent Document 1, the ability to pass through a stenosis site, the followability of a bent blood vessel, and the force required to insert a medical balloon catheter into the blood vessel The kink resistance can be cited as the transmission property and the performance related to this transmission property. On the other hand, Patent Document 1 discloses a configuration in which each performance is improved by gradually reducing the rigidity of the outer shaft toward the distal end side. On the other hand, Patent Document 2 discloses a configuration that improves the passability and followability among the above-mentioned performances by tapering the tip portion of the balloon. However, in any configuration, there is no disclosure of a technique for improving each of the above performances by improving the configuration of the portion where the balloon is provided, and there is room for improvement in this regard.

  The present invention has been made in view of the above circumstances, and has as its main purpose to improve the operability of the balloon catheter by improving the configuration in the region where the balloon is provided and in the peripheral region. .

  Hereinafter, means and the like effective for solving the above-described problems will be described while showing functions and effects as necessary. In the following, in order to facilitate understanding, a corresponding configuration example in the embodiment of the invention is appropriately shown in parentheses, etc., but is not limited to the specific configuration shown in parentheses.

  The balloon catheter (balloon catheter 10) of the present invention is provided so as to pass through the outer tube (distal shaft 13) through which fluid flows into the inner lumen (inner lumen 13a) and the inner lumen of the outer tube, An inner tube (inner shaft 14) provided to extend toward the distal end side of the outer tube and through which a guide wire (guide wire G) is inserted into a lumen (lumen 14a), a distal end region of the outer tube, and the inner tube A hollow balloon (balloon 16, 61, 91) that is held in an extension region of the tube and expands or contracts when fluid flows through the lumen of the outer tube, and the balloon in the inner tube includes The covered covering region (extension region 36) becomes lower in rigidity continuously or stepwise from the proximal end side to the distal end side. Characterized in that it is formed Te Unishi.

  According to this configuration, the distal end side rigidity is lower than the proximal end side in the region covered with the balloon, and as a result, the distal end side rigidity is lower than the proximal end side in the region where the balloon of the balloon catheter is provided. Become. Thereby, the followability of the balloon catheter to the bent blood vessel (or guide wire) and the ability to transmit force when the balloon catheter is inserted into the body can be enhanced in the region where the balloon is provided.

  In addition, “held in the tip region of the outer tube and the extension region of the inner tube” includes not only the configuration in which the balloon is joined (fixed) to the tip region of the outer tube and the extension region of the inner tube, but also the balloon. A configuration in which another member joined to (fixed) is joined (fixed) to the outer tube or the inner tube is also included.

  “Rigidity” specifically refers to “bending stiffness (bending moment)”, and is a value proportional to the product of Young's modulus (longitudinal elastic modulus) and cross-sectional secondary moment.

  The covering area is formed so that the cross-sectional area in the direction perpendicular to the axial direction decreases continuously or stepwise from the base end side toward the tip end side, thereby increasing the rigidity of the covering area. It is preferable to lower continuously or stepwise from the side toward the tip side. In this case, the above-described excellent effect can be achieved by a relatively simple method of changing the cross-sectional area of the covering region.

  By forming the covering region so that the outer diameter decreases continuously or stepwise from the base end side toward the tip end side, the cross-sectional area of the covering region is directed from the base end side toward the tip end side. It is good to make it small continuously or in steps. In this case, the above-described excellent effect can be achieved by a relatively simple method of changing the outer diameter of the covering region (or reducing the thickness). In addition, according to this configuration, it is possible to improve the passage of the balloon catheter when passing through a stenosis site.

  Making the outer diameter on the distal end side of the covering region smaller than the proximal end side as described above forms stepped portions (stepped portions 37, 71, 105) in the middle of the length direction in the covering region of the inner tube. This can be achieved.

  The balloon includes a distal-side fixed region (tip-side leg regions 45 and 96), a distal-side tapered region (tip-side cone regions 44, 62, and 95) that is reduced in diameter toward the distal end, and a maximum balloon size when inflated. Straight tube region (straight tube region 43, 64, 94) serving as a radial region, proximal taper region (proximal cone region 42, 63, 93) reduced in diameter toward the proximal end, and proximal fixed region In the configuration having the (base end side leg regions 41, 65, 92) in this order from the distal end side, the position of the stepped portion is more proximal than the region covered by the distal end side tapered region of the balloon. It is good that it is on the side, and it is on the tip side with respect to the fixing portion between the balloon and the outer tube. In this case, when the balloon is in a deflated state, in the region where the rigidity is higher than the surrounding due to the wrapping around the inner tube of the balloon, the rigidity may be gradually decreased from the proximal end side toward the distal end side. it can.

  Further, it is preferable that the position of the stepped portion is located on the proximal end side with respect to the region covered with the straight tube region of the balloon and on the distal end side with respect to the fixing portion between the balloon and the outer tube. In this case, a region where the rigidity of the inner tube is lowered is arranged with respect to the portion of the straight tube region where the rigidity is particularly high in the wrapping region around the inner tube of the balloon, and the rigidity due to the straight tube region is increased. Can be suppressed as much as possible.

  Furthermore, it is preferable that the position of the stepped portion is located on the proximal end side with respect to the proximal end side tapered region of the balloon and on the distal end side with respect to the fixing portion between the balloon and the outer tube. In this case, an area where the rigidity of the inner tube is lowered is arranged over the entire area around the inner tube of the balloon, and the increase in rigidity due to the wrapping around the inner tube of the balloon is minimized. Can be suppressed.

  In a configuration in which a contrast body (contrast rings 47, 72, 74, 109) is further provided in the covered region, the contrast body may be disposed on the tip side of the stepped portion. By arranging the contrast body having relatively high rigidity in this manner in the region where the rigidity on the tip side of the stepped portion is lowered in the covering region, the influence of the change in rigidity due to the contrast body is reduced.

  The contrast body may be attached with its base ends (end surfaces 47a, 72a) in contact with the stepped portion. In this case, even when the balloon catheter is inserted into the body or when the balloon portion passes through the stenotic region of the blood vessel, even if a load is applied toward the proximal end with respect to the contrast body, the load is applied at the stepped portion. It is received and it is prevented that the position of a contrast object shifts. Furthermore, the positioning when attaching the contrast body to the inner tube is facilitated.

  Making the outer diameter on the distal end side of the covering region smaller than that on the proximal end side as described above can be realized by forming a tapered region (tapered region 111) that narrows toward the distal end side in the covering region. In particular, according to this configuration, the change in rigidity becomes continuous, and the kink resistance of the balloon catheter can be improved.

  Moreover, in the structure which forms a taper area | region as mentioned above, it is good to make the whole said covering area | region into the said taper area | region. In this case, the change in rigidity becomes continuous over the entire covered region, and the kink resistance of the balloon catheter can be further improved.

  The guide wire has an insertion hole (inner cavity 18a) through which the guide wire is inserted, and the insertion hole is fixed to the distal end side of the covering region so as to communicate with the inner tube, and from the covering region. Further, a distal tip body (tip tip body 18) having low rigidity is further provided, and the distal tip side (tip leg regions 45, 96) of the balloon is fixed to the distal tip body. It is good to set it as the structure hold | maintained through the said inner tube through. By providing the distal tip body in this way, the followability of the balloon catheter is enhanced. In addition, since the fixed portion between the distal tip body and the inner tube is in the region covered with the balloon, the possibility of detachment of the distal tip body during insertion of the balloon catheter into the body is reduced. Furthermore, since the tip tip body is fixed to the tip side of the covering region where the rigidity is lowered, it is possible to prevent the rigidity from becoming extremely high at the fixing portion between the inner tube and the tip tip body, It becomes possible to improve the kink resistance of the balloon catheter.

  The balloon includes a distal-side fixed region (tip-side leg regions 45 and 96), a distal-side tapered region (tip-side cone regions 44, 62, and 95) that is reduced in diameter toward the distal end, and a maximum balloon size when inflated. Straight tube region (straight tube region 43, 64, 94) serving as a radial region, proximal taper region (proximal cone region 42, 63, 93) reduced in diameter toward the proximal end, and proximal fixed region In the configuration having the (base end side leg regions 41, 65, 92) in this order from the distal end side, a region where the fixing portion of the inner tube and the distal tip body is covered by the distal end side tapered region It is good to place in. When the balloon is in a deflated state, the rigidity of the distal-side tapered region of the balloon catheter decreases from the proximal side to the distal side according to the amount wound around the inner tube of the balloon. On the other hand, the fixing portion between the inner tube and the distal tip body is higher in rigidity than the fixing portion in the inner tube compared to the base end side. Under such circumstances, by arranging the fixing part in the region covered with the tip side taper region as described above, the influence of the increase in rigidity at the fixing part is reduced, and the rigidity balance with the base end side is good. It will be something.

  It is preferable to provide the inner tube so that the distal end of the inner tube is positioned on the proximal end side with respect to the fixed portion between the balloon and the distal tip body. A configuration is also possible in which the inner tube is overlapped on the inside and outside of the fixing part between the balloon and the tip end body, but in this case, there is a possibility that the fixing part may have extremely high rigidity with respect to the tip side. is there. On the other hand, by setting the distal end of the inner tube to the proximal side with respect to the fixed portion between the balloon and the distal tip body, the rigidity at the fixed portion can be lowered, and the kink resistance of the balloon catheter is improved. It is done.

  In a configuration in which the contrast region (contrast rings 74 and 109) is further provided in the covering region, the contrast member has a step portion (step difference) generated at a fixed portion between the covering region and the tip part. It is good to attach to the part 73,108). In this case, when the balloon catheter is inserted into the body or when the periphery of the balloon passes through a stenotic part of the blood vessel, it is difficult to apply a load to the contrast body, and the contrast body is prevented from being displaced. . Furthermore, the positioning when attaching the contrast body to the inner tube is facilitated.

  In a configuration in which two contrast bodies are provided in the covering region, the base end is brought into contact with a step portion (also referred to as a first step portion) formed to change the outer diameter of one of the contrast bodies. In addition, the other contrast body may be attached with the tip abutting against a stepped portion (also referred to as a second stepped portion) generated at a fixing portion between the covering region and the tip end body.

  Furthermore, in the said structure, it is good to set the position of a 1st level | step-difference part and a 2nd level | step-difference part so that a contrast body may be installed in each of the position corresponding to the base end part and front-end | tip part of a straight tube | pipe area | region of a balloon. . Specifically, the first step portion is formed in the vicinity of the boundary line between the straight tube region and the proximal side taper region of the balloon, and the second step is formed in the vicinity of the boundary line between the straight tube region and the distal side taper region of the balloon. The position of the fixing portion between the tip end body and the extension region of the inner tube is set so that the portion is positioned. In this case, the position of the straight tube region can be more easily grasped during the treatment, and the simplification is realized by using each step portion. Furthermore, the above-mentioned effects due to the contact of the contrast body with each stepped portion can also be achieved.

  Fixing is performed such that the fixing region (tip base end portion 51) fixed to the inner tube in the tip end body is lower in rigidity than the region close to the fixing region. It is preferable to provide a rigidity reduction structure (slit 52) in the region. Thereby, it is suppressed that rigidity becomes high locally in the fixed site | part of an inner tube and a front-end | tip tip body, and the kink resistance of a balloon catheter is improved.

  In addition, as the “rigidity-reducing structure”, a slit, a groove, or a spiral cut extending in the axial direction (length direction), a hole penetrating the tube wall of the tip end body, and the like are conceivable.

  Further, a tip taper region (tip tip region 53) is preferably provided on the tip side of the tip tip body so as to become thinner toward the tip. In this case, the passage of the balloon catheter when passing through the stenosis site can be improved. In particular, the tip taper region may be formed by polishing. For example, although the structure which heats and forms a taper shape is also assumed, there exists a possibility that a front-end | tip tip body may harden | cure in this case. On the other hand, by forming the tapered shape by polishing, such hardening is prevented, and the above-described effect due to the provision of the chip tapered region is surely exhibited.

  Further, the diameter of the insertion hole of the tip end body is preferably substantially the same as the outer diameter of the guide wire. Specifically, it may be 0.014 mm. Along with this, the outer diameter of the distal tip body can also be reduced, and the passage of the balloon catheter when passing through the stenotic site is enhanced.

  The balloon is a distal-side fixed region (tip-side leg regions 45, 96), a distal-side tapered region (tip-side cone regions 44, 95) that is reduced in diameter toward the distal end, and a maximum diameter portion of the balloon when inflated. Straight tube region (straight tube region 43, 94), proximal taper region (proximal cone region 42, 93) reduced in diameter toward the proximal end, and proximal fixed region (proximal leg region 41, 92) in this order from the distal end side, the length dimension along the axial direction of the balloon catheter in the distal tapered region is set along the axial direction of the balloon catheter in the proximal tapered region. It should be larger than the length dimension. In this case, the ratio of the tip side taper region to the entire length of the balloon can be increased, and the tip side taper region can be inclined as gently as possible. As a result, when the balloon is in a deflated state, the outer diameter changes gradually in the portion from the distal end side to the straight tube region, and the passing property when the balloon catheter is inserted into the body is improved. This is because when the change in the outer diameter is abrupt, it becomes a stepped shape at that point, making it difficult to pass through a stenosis site or the like in the blood vessel.

  In addition, by making the length dimension along the axial direction of the balloon catheter of the tip side taper region substantially the same as that of the straight tube region, the ratio of the tip side taper region to the overall length of the balloon can be further increased, and the above effect Becomes more prominent.

  In addition to or in place of the above means, the following means can be considered.

  An outer tube (distal shaft 13) through which a fluid flows in the inner cavity (inner cavity 13a) and an inner tube of the outer tube are provided so as to extend to the distal end side of the outer tube. The inner tube body (inner shaft 14, tip tip body 18) through which the guide wire (guide wire G) is inserted into the lumen (inner lumen 14a), the distal end region of the outer tube, and the extended region of the inner tube body A hollow balloon (balloon 91) that is fixed and expands or contracts when fluid flows through the lumen of the outer tube, and the balloon is fixed to the outer peripheral surface of the inner tube body. Tip side fixed region (tip side leg region 96), tip side tapered region (tip side cone region 95) reduced in diameter toward the tip, during expansion A tip region (tip tip region 53) that has a straight tube region (straight tube region 94) that becomes the maximum diameter portion of the rune in this order from the tip side and protrudes to the tip side of the balloon in the inner tube body. The outer peripheral surface of each of the distal end region, the distal end side fixed region, and the distal end side tapered region is distal end side in the contracted state of the balloon. Each region is formed so as to have a continuous taper shape toward the surface.

  In this case, when the balloon is in a deflated state, the outer peripheral surface of the distal end portion of the balloon catheter is continuously tapered so that the diameter is reduced toward the distal end side, so that the followability and passability of the balloon catheter can be improved.

  Further, in the deflated state of the balloon, each outer peripheral surface of the tip region, the tip side fixed region, and the tip side taper region is continuously tapered toward the tip side and is on the same surface. It is preferable to form a region. In this case, the above effect becomes more remarkable.

  The “inner tube body” is not limited to a single member, and may be a plurality of members. For example, the inner tube body has an inner tube (inner shaft 14) having a lumen (inner lumen 14a) through which the guide wire is inserted, and a lumen (inner lumen 18a) through which the guide wire is inserted. It is also possible to provide a tip tip body (tip tip body 18) that is fixed to the tip end side of the inner tube so that the cavity communicates with the inner lumen of the inner tube and has lower rigidity than the inner tube. Good.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic overall side view of a balloon catheter 10.

  As shown in FIG. 1, the balloon catheter 10 includes a catheter shaft 11 to 14, a hub 15 attached to a proximal end portion (proximal end portion) of the catheter shaft 11 to 14, and a distal end of the catheter shaft 11 to 14. And a balloon 16 attached to the portion (distal end portion).

  The catheter shafts 11 to 14 are composed of a plurality of tubular shafts (tubes). When viewed from the proximal end side, the proxy shaft 11 as a proximal shaft, the mid shaft 12 as an intermediate shaft, and the distal shaft. There is a distal shaft 13. An inner shaft 14 is inserted into the distal shaft 13. In this regard, the distal shaft 13 can be referred to as an outer shaft (outer tube), and the inner shaft 14 can be referred to as an inner shaft (inner tube).

  Among these shafts 11 to 14, a fluid lumen that guides the compressed fluid supplied through the hub 15 into the balloon 16 by the lumens 11 a to 13 a of the proxy shaft 11, the mid shaft 12, and the distal shaft 13. Is formed. Also, a guide wire lumen is formed by the inner lumen 14 a of the inner shaft 14.

  The proxy shaft 11 is made of a metal such as stainless steel or nickel titanium alloy. In addition, it is not limited to metal, It is good also as a product made from a synthetic resin. The proximal shaft 11 has a length of just over 1 m, the hub 15 is joined to the base end portion thereof, and the midshaft 12 is joined to the distal end portion thereof. The outer periphery of the proxy shaft 11 may be coated with a fluororesin such as PTFE.

  The mid shaft 12 is made of synthetic resin, and its material, thickness, outer diameter, and the like are set so that the rigidity is lower than that of the proxy shaft 11. In the balloon catheter 10, as a part of the required main performance, the followability to the bent blood vessel (or the guide wire G) and the force transferability when the balloon catheter 10 is inserted into the body (pushability) ) And in order to improve both these performances, it is necessary to make the rigidity of the front end side of the balloon catheter 10 low with respect to the base end side. In this case, by providing the mid shaft 12 having rigidity lower than that of the proxy shaft 11 as described above, the following property and the transmission property are enhanced. The proxy shaft 11 is provided with a core wire 17 for adjusting rigidity, and the core wire 17 enters the mid shaft 12 (see FIG. 2). Further, the core wire 17 penetrates into the distal shaft 13.

  Here, the structure of the joint portion (region C1 in FIG. 1) between the proxy shaft 11 and the mid shaft 12 will be described in detail with reference to FIG. FIG. 2 is a longitudinal sectional view showing a configuration of a joint portion between the proxy shaft 11 and the mid shaft 12.

  As shown in FIG. 2, the proximal shaft 11 is formed with a tapered region 21 so as to become narrower toward the tip, and further on the tip side thereof, a rigidity-decreasing region in which the stiffness is lowered as compared with other parts. 22 is formed. Among these regions 21 and 22, the rigidity reduced region 22 has a length dimension (length dimension in the axial direction) larger than that of the tapered region 21.

  The tapered region 21 is formed by continuously reducing the inner diameter and the outer diameter toward the tip side, but is not limited to this, and the inner diameter is constant and the thickness is continuously reduced. You may form by doing. The taper region 21 has a lower rigidity than the region on the proximal end side, and further has a continuously lower rigidity toward the distal end side.

  The rigidity reduction region 22 has a reduced rigidity due to a smaller outer diameter than the taper region 21 and the base end side (L2 <L1). In this case, the outer diameter and thickness of the rigidity reduction region 22 are the same throughout. Further, the rigidity reduction region 22 is further provided with a rigidity reduction structure. In detail, as the rigidity reducing structure, a spiral cut 23 is formed continuously in the length direction of the shaft. Moreover, it forms so that the pitch of a notch may become narrow toward the front end side. This pitch means the distance between the notches 23 arranged in the length direction when viewed in the state of FIG. With the above configuration, the rigidity of the rigidity reduction region 22 continuously decreases toward the tip. The rigidity-reducing structure is not limited to the spiral cut 23 described above. For example, a slit or groove extending in the length direction or a hole penetrating the tube wall of the proxy shaft 11 may be used as the rigidity-reducing structure. .

  The mid shaft 12 is joined to the taper region 21 by an adhesive or heat welding in a state where the rigidity reduction region 22 of the proxy shaft 11 is inserted into the inner cavity 12a. In this case, the rigidity reduction region 22 is not joined. That is, in the proxy shaft 11, only the tapered region 21 is a joining region with respect to the midshaft 12, and the proximal end side and the rigidity reduction region 22 with respect to the tapered region 21 are not joining regions with respect to the midshaft 12.

  The outer diameter and inner diameter of the midshaft 12 are substantially the same throughout, and the outer diameter L3 is smaller than the outer diameter L1 on the proximal end side relative to the tapered region 21 of the proxy shaft 11. (Outer diameter L3 <L1). The outer diameter L3 of the mid shaft 12 may be substantially the same as the outer diameter L1 of the proxy shaft 11.

  As described above, the rigidity reduction region 22 is formed in the proxy shaft 11 and the rigidity reduction region 22 is inserted into the midshaft 12, so that the rigidity of the proxy shaft 11 is relatively high. In particular, the rigidity tends to continuously decrease from the proximal end side toward the distal end side at the joint portion with the low mid shaft 12, and the kink resistance at the time of introducing the balloon catheter 10 into the body is improved.

  In particular, by adopting a configuration in which the rigidity reduction region 22 is not used as a joining region, the cut 23 and the like are prevented from being blocked by an adhesive or the like, and the function of the rigidity reduction region 22 can be reliably exhibited. Further, since the outer diameter and thickness of the rigidity reduction region 22 are the same throughout, that is, the rigidity reduction region 22 is not positively tapered, the rigidity reduction such as the pitch of the cuts 23 is reduced. The structure can be easily designed and formed.

  Furthermore, by forming the tapered region 21 in the proxy shaft 11 and joining the midshaft 12 to the tapered region 21, the joining region is suppressed while suppressing a local increase in rigidity in the joining region. In this case, the outer diameter of the balloon catheter 10 can be prevented from becoming large. The balloon catheter 10 is inserted into the body via a guiding catheter. Under such circumstances, assuming a configuration in which the outer diameter increases at a midway position in the length direction of the balloon catheter 10, There is a concern that the degree of freedom in operability of the balloon catheter 10 is reduced. In particular, in recent years, there is a treatment method in which two catheters are inserted into a guiding catheter. In this case, it is necessary to prevent the outer diameter from becoming as large as possible in the middle position. On the other hand, each of the above problems can be solved by forming the tapered region 21 as described above and using the tapered region 21 as a bonding region. Incidentally, the configuration relating to the above-mentioned joining may be applied to a catheter that does not have the balloon 16.

  The proximal end portion of the distal shaft 13 is joined to the distal end portion of the mid shaft 12. The distal shaft 13 is made of synthetic resin, and its material, thickness, outer diameter, and the like are set so that the rigidity is lower than that of the mid shaft 12. Further, the inner shaft 14 is inserted into the distal shaft 13 as already described. The inner shaft 14 is made of synthetic resin, and its material, thickness, outer diameter, and the like are set so that its rigidity is lower than that of the mid shaft 12. Furthermore, the material, thickness, and outside of the distal shaft 13 and the inner shaft 14 are set so that the rigidity of the portion having the double structure of the distal shaft 13 and the inner shaft 14 is lower than that of the mid shaft 12. The diameter is set. If the rigidity is adjusted by the core wire 17, the rigidity of the distal shaft 13 or the inner shaft 14 itself may be higher than that of the mid shaft 12. A port portion 31 for the inner shaft 14 is formed with respect to the proximal end portion of the distal shaft 13.

  Here, the port unit 31 and the related configuration (region C2 in FIG. 1) will be described in detail with reference to FIG. FIG. 3 is a longitudinal sectional view showing the configuration around the port portion 31.

  As shown in FIG. 3, a port portion 31 is formed on the distal shaft 13 so as to open outward from the outer peripheral surface. The port portion 31 has a cylindrical shape and is formed so as to slightly enter the lumen 13a side from the outer peripheral surface of the distal shaft 13. The base end portion 35 of the inner shaft 14 is inserted into the port portion 31, and the inner peripheral surface of the port portion 31 and the outer peripheral surface of the base end portion 35 are joined. Although this joining is performed by heat welding, it may be joined using an adhesive or the like.

  In the above configuration, the port portion 31 is formed without projecting outward with respect to the outer peripheral surface of the distal end side region of the distal shaft 13 relative to the port portion 31. Specifically, the port portion 31 is formed so as to be recessed inward with respect to the outer peripheral surface of the region on the tip end side. In other words, the outer peripheral side wall portion of the distal shaft 13 in the port portion 31 is partially removed. In addition, in the configuration depressed in this way, the compressed fluid supplied from the hub 15 side is ensured by joining the port portion 31 and the base end portion 35 over the entire inner peripheral surface of the port portion 31. Leaking around the port portion 31 is suppressed. The base end portion 35 of the inner shaft 14 is formed in accordance with the shape of the outer opening of the port portion 31, and the base end portion 35 does not extend outward from the port portion 31. The base end portion 35 of the inner shaft 14 may be configured to enter the inside of the outer opening of the port portion 31.

  As described above, since the outer diameter around the port portion 31 is formed to be smaller than that at the tip end side, the rigidity around the port portion 31 may be extremely higher than the tip end side of the port portion 31. It is suppressed. That is, in the distal shaft 13, the periphery of the port portion 31 is formed with the port portion 31 and further has a joining region between the port portion 31 and the inner shaft 14. Get higher. On the other hand, when the port portion 31 is depressed as described above, a decrease in rigidity around the port portion 31 is expected, and the rigidity is suppressed from becoming extremely higher than that at the tip end side.

  Further, assuming a configuration in which the port portion 31 protrudes outward from the outer peripheral surface on the distal end side, the outer diameter becomes large at an intermediate position in the length direction of the balloon catheter 10. Then, as described above, there may be a problem that the operability of the balloon catheter 10 in the guiding catheter is lowered. On the other hand, since the port portion 31 does not protrude outward from the outer peripheral surface on the front end side as described above, the above problem is solved.

  Next, the configuration around the balloon 16 (region C3 in FIG. 1) will be described in detail with reference to FIG. FIG. 4 is an explanatory diagram for explaining the configuration around the balloon 16. FIG. 4 shows a case where the balloon 16 is in an inflated state.

  As shown in FIG. 4, the inner shaft 14 provided to be inserted into the distal shaft 13 is extended to the front end side with respect to the distal shaft 13. A tip end body 18 is provided at the tip of the extension region 36 of the inner shaft 14. In such a configuration, the balloon 16 is joined to the distal shaft 13 at the proximal end, and joined to the distal tip body 18 at the distal end so as to cover the outer peripheral surface of the extension region 36 of the inner shaft 14. Is provided. In this regard, the extended region 36 can be referred to as a covered region covered with the balloon 16.

  The balloon 16 is made of synthetic resin, and is formed so that the inner diameter and the outer diameter are changed in a plurality of stages in the expanded state. That is, the balloon 16 has a base end side leg region (base end side joint region) 41 joined to the distal shaft 13 and a taper base so that the inner diameter and the outer diameter are increased toward the distal end side. An end cone region (base end inclined region or base end taper region) 42, a straight tube region 43 having the same inner diameter and outer diameter throughout the length direction and forming the maximum outer diameter region of the balloon 16; The tip side cone region (tip side inclined region or tip side taper region) 44 is tapered so that the inner diameter and the outer diameter are reduced toward the tip side, and the tip side leg joined to the tip part 18 It has the area | region (front end side junction part) 45 in this order from the base end side.

  The length dimension X1 of the distal end side cone region 44 is larger than the length dimension X3 of the proximal end side cone region 42 (X1> X3). Furthermore, the axial length X1 of the balloon catheter 10 in the distal cone region 44 is substantially the same as the axial length X2 of the straight tube region 43 (X1≈X2). By setting the length dimension of the distal end side cone region 44 as described above, the ratio of the distal end side cone region 44 to the entire length of the balloon 16 can be increased, and the inclination of the distal end side cone region 44 is minimized. It becomes possible to make it gentle. As a result, the balloon 16 is deflated, and the proximal end cone region 42, the straight tube region 43, and the distal end cone region 44 (inflated and deflated regions including these regions) in the balloon 16 are the inner shaft 14 and the distal tip body 18. In the state of being wound around the outer peripheral surface of the balloon (hereinafter, this state is also referred to as a deflated state of the balloon 16), the outer diameter changes gradually in the portion from the distal end side to the straight tube region 43, and the balloon catheter 10 The crossability when inserting into the body is improved. This is because when the change in the outer diameter is abrupt, it becomes a stepped shape at that point, making it difficult to pass through a stenosis site or the like in the blood vessel.

  In the configuration in which the balloon 16 is formed by a plurality of wings (for example, three wings), when the balloon 16 is in the contracted state, each of the wings individually extends around the extension region 36 of the inner shaft 14 and the tip part 18. It will be in a state of being wrapped around. Specifically, when the balloon 16 is changed from the inflated state to the deflated state, the inflated and deflated regions of the balloon 16 are folded so that a plurality of wings standing perpendicularly to the axial direction are formed at equal intervals. The wings are wound around the extension region 36 of the inner tube 14 and the tip end body 18 to be in a contracted state.

  The front end leg region 45 of the balloon 16 is bonded to the outer peripheral surface of the front end tip body 18. In contrast, the joining of the proximal leg region 41 to the distal shaft 13 has a characteristic configuration. Therefore, the following configuration will be described. In addition, although each joining is performed by heat welding, you may make it join using an adhesive agent.

  In the distal shaft 13, the inner diameter of the distal end portion 32 is increased with respect to the proximal end side (hereinafter, the distal end portion 32 is also referred to as a distal end enlarged diameter portion 32). In addition, in this embodiment, although the outer diameter of the front end enlarged part 32 of the distal shaft 13 is also enlarged with respect to the base end side, the said outer diameter is good also as the base end side. That is, the inner diameter of the distal end enlarged portion 32 may be increased by thinning the distal end enlarged portion 32 of the distal shaft 13 with respect to the proximal end side.

  The outer peripheral surface of the base end side leg region 41 of the balloon 16 is joined to the inner peripheral surface of the distal end enlarged diameter portion 32 of the distal shaft 13 by thermal welding. In this case, the entire outer peripheral surface of the base end side leg region 41 is joined to the inner peripheral surface of the distal end enlarged diameter portion 32.

  The joining operation of the proximal end leg region 41 and the distal end enlarged diameter portion 32 will be briefly described. When joining the proximal end leg region 41 and the distal end enlarged diameter portion 32, a metal rod having a flat outer peripheral surface is disposed on the lumen side of the distal enlarged diameter portion 32 and the proximal end leg region 41, and the distal end in this state Heating and pressing are performed from the outer peripheral surface side of the enlarged diameter portion 32 using a welding device. Thereby, the base end side leg area | region 41 and the front-end | tip enlarged diameter part 32 are joined by heat welding. In this case, since the metal rod is arranged on the inner side as described above, the flatness of the joint portion between the proximal end leg region 41 and the distal end enlarged diameter portion 32 is improved, and the proximal end leg region 41 is expanded at the distal end. In the configuration positioned inside the diameter portion 32, the influence of the compressed fluid supplied via the hub 15 on the inflow into or out of the balloon 16 is reduced.

  As described above, since the positional relationship between the proximal end leg region 41 and the distal end enlarged diameter portion 32 is set, heat is applied to the proximal end cone region 42 and the straight tube region 43 of the balloon 16 during heat welding. It is possible to prevent as much as possible. When heat is applied to the proximal-side cone region 42 or the straight tube region 43, the portion is cured, and the characteristics relating to expansion / contraction in the balloon 16 may be deteriorated. It is possible to suppress such deterioration of characteristics.

  Further, in the configuration in which the proximal end leg region 41 is joined to the distal shaft 13 so as to be on the outer peripheral side as in the prior art, the influence of thermal welding is caused by the proximal end cone region 42 and the straight tube region 43. Therefore, heat is not applied to the entire base end side leg region 41, but only to a part of the base end side leg region 41 near the base end. In this case, the area of heat welding becomes narrow, and there is a possibility that the bonding strength between the balloon 16 and the distal shaft 13 cannot be secured sufficiently. On the other hand, according to the configuration of the present embodiment, since the entire base end side leg region 41 can be bonded as described above, the bonding strength can be sufficiently ensured.

  In the conventional configuration, only a part of the proximal end leg region 41 near the proximal end is joined as described above, so that the distal end side of the proximal end leg region 41 floats with respect to the distal shaft 13. On the other hand, according to the configuration of the present embodiment, the proximal end leg region 41 does not float unlike the prior art, so the outer diameter of the joint portion between the balloon 16 and the distal shaft 13 is made larger than before. Can be kept small.

  As described above, the distal end side cone region 44 is larger in length than the proximal end side cone region 42. Therefore, even if the front end leg region 45 is joined to the outer peripheral surface of the front end tip body 18 by heat welding, the influence of heat on the straight pipe region 43 is low. On the other hand, if the same configuration as that of the proximal end leg region 41 is applied to the distal leg region 45, the configuration of the distal tip body 18 may be complicated, and the balloon catheter 10 inserted into the body may be introduced. However, a complicated structure is not preferable. Therefore, it is preferable to join the front end leg region 45 to the outer peripheral surface of the front end tip body 18 as described above.

  The extension region 36 of the inner shaft 14 will be described in detail.

  The extended region 36 of the inner shaft 14 is covered with the outer peripheral surface of the balloon 16 as described above. As shown in FIG. 4B, the extension region 36 is thinned at a middle position in the length direction so that the outer diameter gradually decreases from the base end side toward the tip end side. Thus, the portion where the thickness changes has a stepped shape (the stepped portion is referred to as a stepped portion 37). However, in the configuration in which the outer diameter is changed as described above, the inner diameter is the same. As a result, the cross-sectional area perpendicular to the axial direction in the extension region 36 gradually decreases toward the tip side, and as a result, the rigidity (bending stiffness or bending moment) of the extension region 36 toward the tip side. It is getting lower step by step. Accordingly, in the region where the balloon 16 of the balloon catheter 10 is provided, the rigidity can be changed so that the distal end side is lowered. Therefore, the followability and transferability of the balloon catheter 10 can be enhanced even in the region where the balloon 16 is provided. Further, the position of the stepped portion 37 is a portion covered with the straight tube region 43 of the balloon 16 in the extended region 36. Thereby, the rigidity can be changed at a position near the middle of the region where the balloon 16 is provided.

  In the extension region 36, in order to improve the visibility of the balloon 16 under X-ray projection and to easily position the balloon 16 at a target treatment site, a metal contrast ring (contrast marker member or (Contrast body) 47 is provided.

  The contrast ring 47 is installed with the base end side end surface 47 a in contact with the stepped portion 37. As a result, even when the balloon catheter 10 is inserted into the body or when the periphery of the balloon 16 passes through the stenotic region of the blood vessel, even if a load is applied toward the proximal end side with respect to the contrast ring 47, the load is stepped. It is received by the part 37 and the position of the contrast ring 47 is prevented from being displaced. Further, the positioning when attaching the contrast ring 47 to the inner shaft 14 is facilitated. Furthermore, by arranging the contrast ring 47 having higher rigidity than the balloon 16 or the like in a region where the rigidity on the tip side of the inner shaft 14 is lower than the stepped portion 37, the influence of the change in rigidity due to the contrast ring 47 is reduced. Is done. Incidentally, the contrast ring 47 is not limited to a metal and may be made of a synthetic resin as long as it performs a contrast function.

  Note that a coating layer is formed in the inner lumen 14 a of the inner shaft 14 in order to improve the sliding property of the guide wire G. As this coating layer, a hydrophilic material such as polyethylene oxide or maleic anhydride may be used, or a hydrophobic material such as a fluororesin such as PTFE may be used. By using a hydrophobic material, swelling of the coating layer can be prevented.

  As shown in FIG. 4C, the distal tip body 18 is attached to the shaft distal end portion 38 of the extension region 36. The tip tip body 18 is formed in a tubular shape from a synthetic resin, and its material, thickness, outer diameter, etc. are set so that the rigidity is lower than that of the inner shaft 14.

  The tip base end portion 51 of the tip tip body 18 covers the shaft tip portion 38 of the extension region 36. And the inner peripheral surface of the chip | tip base end part 51 and the outer peripheral surface of the shaft front-end | tip part 38 are joined by heat welding. The lumen 18a of the tip end body 18 is communicated with the lumen 14a of the inner shaft 14, and both the lumens 14a, 18a are on the same axis. A guide wire lumen is formed by both the lumens 14a and 18a. Note that the inner diameter of the distal tip body 18 is substantially the same as the outer diameter of the guide wire G, specifically 0.014 mm.

  Here, the shaft distal end portion 38 is located on the proximal end side with respect to the joining position between the distal end side leg region 45 of the balloon 16 and the distal end tip body 18. For example, a configuration in which the shaft distal end portion 38 is located on the distal end side with respect to the distal end side leg region 45 is assumed, but in this case, the joint position between the shaft distal end portion 38 and the distal end tip body 18 is located outside the balloon 16. There is a possibility that the tip tip body 18 may be detached when passing through a stenosis portion of the blood vessel. On the other hand, by setting the shaft distal end portion 38 to the proximal end side with respect to the distal end side leg region 45, the possibility of occurrence of such inconvenience is reduced. Further, a configuration is also possible in which the shaft tip portion 38 is overlapped on the inside and outside of the joining position of the tip side leg region 45 and the tip part 18, but in this case, the joining region is more rigid on the tip side than that. There is a risk of becoming extremely high. On the other hand, by setting the shaft distal end portion 38 to the proximal end side with respect to the distal leg region 45, the rigidity in the joining region can be lowered, and the kink resistance of the balloon catheter 10 is improved.

  Further, the joint portion between the shaft distal end portion 38 and the tip proximal end portion 51 is located on the proximal end side with respect to the region covered with the distal end side leg region 45 of the balloon 16, and more specifically, the distal end cone of the balloon 16. It is in an area covered by the area 44. In other words, the joint portion is in a region where the tip cone region 44 of the balloon 16 is wound when the balloon 16 is in a deflated state. Here, when the balloon 16 is in a deflated state, the rigidity of the distal end side cone region 44 of the balloon catheter 10 decreases from the proximal end side toward the distal end side in accordance with the amount of the balloon 16 wound. On the other hand, the joint portion between the shaft distal end portion 38 and the tip proximal end portion 51 has higher rigidity than the joint portion in the extension region 36 as compared to the proximal end side. In such circumstances, since the joint portion between the shaft distal end portion 38 and the tip proximal end portion 51 is set in the region where the distal-end-side cone region 44 is wound as described above, the influence of the increase in rigidity at the joint portion is affected. And the balance of rigidity with the base end side is improved.

  The tip base end portion 51 is provided with a rigidity reducing structure for the tip tip body 18. Specifically, slits 52 extending in the length direction are juxtaposed in the circumferential direction at the tip base end portion 51. Thereby, it is suppressed that rigidity becomes locally high in the joining position of the front-end | tip tip body 18 and the inner shaft 14, and the kink resistance is improved. However, the end portion on the front end side of the slit 52 does not reach the front end side from the shaft front end portion 38.

  The rigidity reducing structure for the tip end body 18 is not limited to the slit 52. For example, the rigidity of a groove or a spiral cut extending in the length direction or a hole penetrating the tube wall of the tip end body 18 is reduced. It is good also as a structure. Further, the rigidity reducing structure may be provided not on the tip end body 18 but on the shaft tip portion 38 of the inner shaft 14.

  The tip tip region 53 on the tip side of the tip 16 in the tip tip body 18 has a tapered shape by reducing the thickness. That is, the outer peripheral surface of the tip end region 53 is tapered so as to become thinner toward the tip end side. Thereby, the passage of the balloon catheter 10 is improved. In addition, the rigidity of the distal tip body 18 gradually decreases toward the distal end side, and the followability, transferability, and kink resistance of the balloon catheter 10 are improved.

  Here, the tapered shape of the tip end body 18 is formed by polishing. For example, although the structure which forms a taper shape by applying heat is also assumed, there exists a possibility that the front-end | tip tip body 18 may harden | cure in this case. On the other hand, by forming the tapered shape by polishing, such hardening is prevented, and the above-described effect due to the tapered tip end region 53 is reliably exhibited.

  The balloon catheter 10 having the above configuration is used as follows.

  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 into the guide wire lumen of the balloon catheter 10 and the guiding catheter, and introduced from the coronary artery entrance to the treatment site (for example, the stenosis site) to the peripheral site. Subsequently, the balloon catheter 10 is introduced along the guide wire G to the treatment target site while performing a push-pull or twist operation. In this case, as described above, the balloon catheter 10 has improved passability, followability, transferability, and kink resistance, so that the introduction operation can be performed satisfactorily. When the balloon 16 reaches the treatment target site, the balloon 16 is expanded with a pressurizer to perform treatment.

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

  In the extended region 36 of the inner shaft 14, a stepped portion 37 is formed at an intermediate position in the length direction so that the outer diameter on the distal end side is smaller than the proximal end side. Thereby, the rigidity of the extension region 36 is lower on the distal end side than on the proximal end side. Accordingly, in the region where the balloon 16 of the balloon catheter 10 is provided, the rigidity can be changed so that the distal end side is lowered. Therefore, the followability and transferability of the balloon catheter 10 can be enhanced in the region where the balloon 16 is provided.

  Furthermore, since the stepped portion 37 is formed as described above, the outer diameter of the distal end portion of the balloon catheter 10 is reduced, and the passage of the balloon catheter 10 when passing through a stenotic site can be improved.

  In the configuration in which the rigidity on the distal end side of the extension region 36 is lower than that on the proximal end side as described above, the distal tip body 18 is bonded to the distal end region. Thereby, it is possible to prevent the rigidity from becoming extremely high at the joint position between the inner shaft 14 and the tip end body 18, and to improve the kink resistance of the balloon catheter 10.

(Second Embodiment)
In the present embodiment, the configuration around the balloon is different from that of the first embodiment. Therefore, the following differences will be described with reference to FIG. In FIG. 5, the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  The balloon 61 in the present embodiment is different from the balloon 16 in the first embodiment, and the length dimension X4 of the distal end side cone region 62 is substantially the same as the length dimension X6 of the proximal end side cone region 63. (X4≈X6). Further, the length dimensions X4 and X6 of the respective cone areas 62 and 63 are smaller than the length dimension X5 of the straight pipe area 64 (X4≈X6 <X5).

  The extended region 36 of the inner shaft 14 is covered with a balloon 61 on the outer peripheral surface thereof in the same manner as in the first embodiment, and the outer region 36 is located at an intermediate position in the length direction from the proximal end side toward the distal end side. A stepped portion 71 is formed so that the diameter decreases stepwise. In this case, the position of the stepped portion 71 is different from that in the first embodiment. That is, as shown in FIG. 5A, the stepped portion 71 is located in the middle of the extension region 36 and on the boundary line between the proximal end cone region 63 and the straight tube region 64 in the balloon 61. . Then, as shown in FIG. 5B, the contrast ring 72 is attached with the end surface 72 a on the base end side in contact with the stepped portion 71.

  In addition, as in the first embodiment, the tip end body 18 is joined to the shaft tip portion 38 of the extension region 36 so as to cover the shaft tip portion 38 from the outside. In this case, the joint portion between the shaft distal end portion 38 and the tip proximal end portion 51 is thicker than the proximal end side, and has a stepped shape. In other words, the diameter of the bonded portion is increased compared to the region around the extension region 36 and the tip end body 18. As shown in FIG. 5A, the stepped portion 73 forming the stepped shape is located in the middle of the extended region 36 and on the boundary line between the straight tube region 64 and the distal end side cone region 62 in the balloon 61. It is formed to do. Then, as shown in FIG. 5C, the contrast ring 74 is attached with the end surface 74a on the distal end side in contact with the stepped portion 73.

  As described above, in this embodiment, the two contrast rings 72 and 74 are attached to the extension region 36 of the inner shaft 14, and the first contrast ring 72 is the base end of the straight tube region 64 of the balloon 61. The other second contrast ring 74 is disposed with respect to the boundary on the distal end side in the straight tube region 64 of the balloon 61. In this case, the visibility of the straight tube region 64 of the balloon 61 under X-ray projection is improved, and the balloon 61 can be more easily positioned at the target treatment site.

  In this configuration, the first contrast ring 72 has an end surface 72a on the base end side that is in contact with the stepped portion 71 formed in the extension region 36 of the inner shaft 14, and thus the contrast ring of the first embodiment. The same effect as described for 47 can be obtained.

  Further, the second contrast ring 74 has an end surface 74 a on the distal end side in contact with a stepped portion 73 in a joining region between the inner shaft 14 and the distal tip body 18. Thereby, when the balloon catheter 10 is inserted into the body or when the periphery of the balloon 61 passes through the stenotic region of the blood vessel, it is difficult to apply a load to the second contrast ring 74, and the position of the second contrast ring 74 is changed. It is prevented that it shifts. Further, it is possible to facilitate positioning when the second contrast ring 74 is attached to the inner shaft 14. Further, by arranging the second contrast ring 74 whose rigidity is higher than that of the balloon 61 or the like in the region where the rigidity is lowered in the inner shaft 14, the influence of the change in rigidity due to the second contrast ring 74 is reduced. In addition, the joint area between the inner shaft 14 and the tip end body 18 has higher rigidity than the surrounding area, but the rigidity is high by attaching the second contrast ring 74 in contact with the stepped portion 73 of the joint area. Areas can be consolidated.

  In this embodiment, the distal shaft 13 shown in the first embodiment is not formed in the distal shaft 13, and the proximal end leg region 65 of the balloon 61 is formed in the distal shaft 13. It joins so that the front-end | tip part of may be covered from an outer side. Further, the number of contrast rings (contrast bodies) 72 and 74 is not limited to two, and may be three or more.

(Third embodiment)
In the present embodiment, the configuration around the balloon is different from that of the first embodiment. Therefore, the following differences will be described with reference to FIGS. 6 is an explanatory diagram for explaining the configuration around the balloon 91, and FIG. 7 is an explanatory diagram for explaining the configuration around the balloon 91 when the balloon 91 is in a deflated state. 6 and 7, the same components as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  The balloon 91 in the present embodiment has a configuration similar to that of the balloon 16 in the first embodiment. That is, it has a proximal leg region 92, a proximal cone region 93, a straight tube region 94, a distal cone region 95, and a distal leg region 96, and the axial direction of the balloon catheter 10 in the distal cone region 95 The length dimension X7 is larger than the length dimension X9 in the axial direction in the proximal-side cone region 93 (X7> X9). The length dimension X7 in the axial direction of the balloon catheter 10 in the distal cone region 95 is substantially the same as the length dimension X8 in the axial direction in the straight tube region 94 (X7≈X8).

  However, the structure of the joining part of each leg area | region 92,96 differs from the said 1st Embodiment. First, the structure of the joining part of the proximal end leg region 92 will be described.

  The proximal end leg region 92 is joined to the inner peripheral surface of the distal end enlarged diameter portion 101 formed on the distal shaft 13 as in the first embodiment. However, the distal diameter expanding portion 101 is smaller in length than the first embodiment, and the proximal end leg region 92 is covered only from the proximal end portion by the distal diameter expanding portion 101 from the outside. Only the covered part is joined. With such a configuration, the joint portion between the proximal leg region 92 and the distal shaft 13 can be separated from the proximal cone region 93 over a predetermined range. Therefore, the influence of heat at the time of heat-welding the base end side leg region 92 and the distal shaft 13 to the base end side cone region 93 and the straight tube region 94 is reduced.

  Next, the structure of the junction part of the front end side leg area | region 96 is demonstrated.

  As shown in FIG. 6B, the inner peripheral surface of the distal leg region 96 is joined to the outer peripheral surface of the distal tip body 18. In this case, the tip side leg region 96 is tapered so that the outer peripheral surface 96a is reduced in diameter toward the tip side (hereinafter also referred to as a tapered outer peripheral surface 96a). The inclination angle of the tapered outer peripheral surface 96a is substantially the same as the inclination angle of the outer peripheral surface formed in a tapered shape of the tip end region 53 in the end tip body 18, and the tapered outer peripheral surface 96a and the tip end of the tip end tip body 53 are the same. The slope of the outer peripheral surface of the region 53 is continuous. That is, there is no surface extending in the direction perpendicular to the axial direction between the two outer peripheral surfaces. Thereby, the passage property of the balloon catheter 10 at the time of letting a stenosis site pass is improved.

  Furthermore, as described above, the distal end cone region 95 of the balloon 91 is larger in length than the proximal end cone region 93, and the distal end cone of the folding wing 98 when the balloon 91 is in a contracted state. The slope in the region 95 is gentle. In particular, as described above, when the length dimension of the distal end side cone region 95 is larger than the length dimension of the proximal end side cone region 93, the thickness of the balloon 91 at the starting point portion 99 on the distal end side of the folding wing 98 is suppressed. The occurrence of a step in the starting point portion 99 is suppressed. As shown in FIG. 7, the inclination angle of the outer peripheral surface of the distal cone region 95 in the deflated state of the balloon 91 is such that the tapered outer peripheral surface 96 a of the distal leg region 96 and the tip distal region 53 of the distal tip body 18. It is substantially the same as the inclination angle of the outer peripheral surface. Therefore, in the deflated state of the balloon 91, the outer peripheral surfaces of the distal end cone region 95, the distal end leg region 96, and the tip distal end region 53 are continuously inclined, and there is an axial direction between the outer peripheral surfaces. On the other hand, there is no surface extending in the vertical direction. Moreover, each outer peripheral surface exists on the same surface. Thereby, the passage property of the balloon catheter 10 at the time of letting a stenosis site pass is improved.

  Next, the extension region 36 of the inner shaft 14 and the configuration related thereto will be described.

  The extension region 36 of the inner shaft 14 is covered with a balloon 91 on the outer peripheral surface in the same manner as in the first embodiment, and has an outer diameter at a midway position in the length direction from the proximal end side toward the distal end side. The step 105 is formed so as to be gradually reduced. In this case, the position of the stepped portion 105 is different from that in the first embodiment. That is, the step 105 is located in the middle of the extension region 36 and on the boundary line between the proximal leg region 92 and the proximal cone region 93 in the balloon 91. Note that, unlike the first embodiment, no contrast ring is provided for the stepped portion 105.

  Unlike the first embodiment, the position of the shaft tip portion 38 of the inner shaft 14 is a region covered with the straight tube region 94. The tip base end 51 of the tip tip body 18 is joined so as to cover the shaft tip 38 from the outside. That is, in the present embodiment, the position of the joint portion between the inner shaft 14 and the tip end body 18 is a region covered with the straight tube region 94. In this regard, it can be said that the tip tip body 18 is provided extending to the base end side so that the tip base end portion 51 is located in a region covered by the straight tube region 94.

  The joint portion between the shaft distal end portion 38 and the tip proximal end portion 51 is thicker than the proximal end side and has a stepped shape. The contrast ring 109 is attached with the end face 109a on the front end side in contact with the step portion 108 forming the step shape.

  As described above, in the present embodiment, the step portion 105 of the extension region 36 is located in the middle of the extension region 36 and is located on the boundary line between the base end side leg region 92 and the base end side cone region 93 in the balloon 91. is doing. Thereby, the region covered by the proximal-side cone region 93, the straight tube region 94, and the distal-side cone region 95 as the inflated and deflated regions in the balloon 91 includes a distal-side region in which the rigidity in the extended region 36 is reduced and The tip end body 18 having a lower rigidity than the extension region 36 is disposed. Since the inflated and deflated regions are regions that wrap around the inner shaft portion in the deflated state of the balloon 91, the rigidity of such regions naturally increases in the deflated state. In this case, by setting the position of the stepped portion 105 as described above, the rigidity of the inner shaft portion is reduced, and as a result, the rigidity of the inflated and deflated region is lowered in the deflated state of the balloon 91. Can do. Thereby, the followability of the balloon catheter 10 can be improved.

  The position of the stepped portion 105 may be closer to the proximal end side than the region covered with the distal end side cone region 95 of the balloon 91, and may be closer to the distal end side than the joint portion between the balloon 91 and the distal shaft 13. Further, it is preferable that the proximal end side of the region covered by the straight tube region 94 of the balloon 91 and the distal end side of the junction portion between the balloon 91 and the distal shaft 13. In this case, at least in the region covered with the straight tube region 94, the distal end side region in which the rigidity in the extended region 36 is reduced and the distal end tip body 18 having lower rigidity than the extended region 36 are disposed. In addition, as in the configuration of the present embodiment, the proximal end side of the balloon 91 is covered with the proximal end cone region 93 and the distal end side of the junction portion between the balloon 91 and the distal shaft 13. Is more preferable.

  Further, the joint portion between the shaft distal end portion 38 and the tip proximal end portion 51 is in a region covered with the straight tube region 94. In the deflated state of the balloon 91, the straight tube region 94 is a portion where the amount of wrapping of the balloon 91 around the inner shaft portion increases, and its rigidity is higher than that of the proximal end side and the distal end side. . Further, this increase in rigidity extends to the entire area where the straight pipe region 94 is provided. On the other hand, the joint portion between the shaft distal end portion 38 and the tip proximal end portion 51 is more rigid than the proximal end side than that in the extended region 36 and the distal end side than that in the distal end tip body 18. In addition, the portion where the contrast ring 109 is provided is also more rigid than the proximal end side than that in the extended region 36 and the distal end side than that in the distal tip body 18. However, the rigidity at the joining portion and the contrast ring 109 is lower than the rigidity due to the straight tube region 94 being wound. In such a situation, by arranging the joint portion and the contrast ring 109 in the region covered with the straight tube region 94 as described above, the influence of rigidity in the joint portion and the contrast ring 109 is caused by the winding of the straight tube region 94. As the rigidity increases, the rigidity becomes smaller, and as a result, the influence of the rigidity due to the joint portion and the contrast ring 109 is reduced.

(Other embodiments)
The present invention is not limited to the contents described in the above embodiments, and may be implemented as follows, for example.

  (1) The modification about the extension area | region 36 of the inner shaft 14 is demonstrated below using FIG. 8, FIG.

  In the configuration shown in FIG. 8, the stepped portions 37, 71, and 105 shown in the above embodiments are not formed in the extended region 36 of the inner shaft 14, and instead the outer diameter is reduced toward the tip side. A tapered region 111 is formed to have a diameter. The tapered region 111 is formed in the middle of the extended region 36. Therefore, in the extended region 36, the proximal end side of the taper region 111 is a large diameter region 112, and the distal end side is a small diameter region 113. Even in this configuration, the rigidity of the extension region 36 is lower on the distal end side than the proximal end side, and accordingly, the distal end side is lowered in the region where the balloons 16, 61, 91 of the balloon catheter 10 are provided. Thus, the rigidity can be changed. In particular, according to this configuration, the change in rigidity is continuous as compared with the above embodiments, and the kink resistance of the balloon catheter 10 can also be improved.

  In the configuration shown in FIG. 9, the tapered region 111 is formed over the entire extended region 36 of the inner shaft 14. As a result, the rigidity of the extension region 36 continuously decreases from the base end side toward the tip end side, and a change in the rigidity occurs over the entire extension region 36. Therefore, the kink resistance of the balloon catheter 10 can be improved more than the configuration of FIG. Incidentally, the base end position of the tapered region 111 of the inner shaft 14 may be set to the base end side with respect to the extension region 36. In this case, the change in the rigidity of the balloon catheter 10 becomes better.

  8 and 9, when the contrast means is provided on the inner shaft 14, a contrast ring may be used in the same manner as in each of the above embodiments. In addition, an ink containing metal powder may be applied to the outer peripheral surface of the extension region 36. It is good also as a structure to print.

  (2) In each of the embodiments described above, the rigidity on the distal end side is reduced by making the outer diameter on the distal end side smaller than the proximal end side in the extended region 36 of the inner shaft 14. It may be changed. For example, as the rigidity reduction structure of the inner shaft 14, a groove that does not penetrate the tube wall is formed in the extension region 36 along the length direction. In this case, the rigidity can be gradually lowered toward the distal end side by increasing the width of the groove toward the distal end side or increasing the number of grooves toward the distal end side.

  In addition, it is not preferable to provide a slit or a spiral cut as the rigidity reduction structure of the inner shaft 14. In this case, there is a possibility that the guide wire lumen may open to the outside in the middle of the extension region 36 and the guide wire G may come out of the opening.

  (3) Further, the outer diameter of the extension region of the inner shaft 14 is made the same in the entire length direction, and instead, the inner diameter of the extension region 36 is gradually or continuously from the proximal end side toward the distal end side. It is good also as a structure which enlarges automatically. Even in this configuration, the cross-sectional area of the cross section in the direction perpendicular to the axial direction of the extension region 36 decreases stepwise or continuously from the base end side to the tip end side, and accordingly, the rigidity also increases. It becomes smaller stepwise or continuously from the proximal side to the distal side.

  (4) In each of the above embodiments, the contrast rings 47, 72, 74, and 109 are attached to the reduced diameter region on the distal end side of the stepped portions 37, 71, and 105 in the extended region 36 of the inner shaft 14. Instead of this, it may be attached to a region closer to the base end than the stepped portions 37, 71, 105. In this case, although the effect on the rigidity of the contrast rings 47, 72, 74, and 109 cannot be reduced, it is inferior to the above embodiments, but the rigidity of the extension region 36 is lower on the distal end side than on the proximal end side. As compared with the above, it is possible to improve the followability and transferability of the balloon catheter 10.

  (5) The joining relationship between the inner shaft 14 and the tip end body 18 may be reversed from the above embodiments. That is, the tip base end portion 51 of the tip tip body 18 may be joined so as to cover the outer peripheral surface of the shaft tip portion 38 of the inner shaft 14.

  (6) The tip tip body 18 may be omitted. In this case, the tip of the inner shaft 14 functions as a tip part by causing the inner shaft 14 to protrude to the tip side from the balloon 16 and further tapering the protruding part. In this configuration, the balloon 16 can be held on the inner shaft 14 by joining the distal end side of the balloon 16 to the inner shaft 14.

  (7) In each of the above embodiments, the balloon 16 is held on the distal shaft 13 by joining the base end side of the balloon 16 to the distal shaft 13. Another member may be interposed between the end side and the distal shaft 13 to hold the balloon 16 on the distal shaft 13.

  (8) In each of the above embodiments, the mid shaft 12 and the distal shaft 13 may be provided as a single shaft. In this case, the proximal shaft 11 becomes the base end side shaft, and the shaft having the mid shaft 12 and the distal shaft 13 as a single piece becomes the front end side shaft. Even if the present invention is applied to a balloon catheter having a catheter shaft having such a configuration, the same effects as those of the above embodiments can be obtained.

  (9) In each of the above embodiments, the guide wire G port portion 31 is provided in the middle of the length of the catheter shaft. Instead, the guide wire G port is provided at the proximal end portion of the catheter shaft. It is good also as a structure which provides a part and inserts the inner shaft which forms the lumen for guide wires over the whole catheter shaft.

The schematic whole side view of the balloon catheter in 1st Embodiment. The longitudinal cross-sectional view which shows the structure of the junction part of a proxy shaft and a mid shaft. The longitudinal cross-sectional view which shows the structure of a port part periphery. Explanatory drawing for demonstrating the structure of a balloon periphery. Explanatory drawing for demonstrating the structure of the balloon periphery in 2nd Embodiment. Explanatory drawing for demonstrating the structure of the balloon periphery in 3rd Embodiment. Explanatory drawing for demonstrating the structure of the balloon periphery in a contracted state. Explanatory drawing for demonstrating the structure of another balloon periphery. Explanatory drawing for demonstrating the structure of another balloon periphery.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Balloon catheter, 13 ... Distal shaft as outer tube, 13a ... Lumen, 14 ... Inner shaft, 14a ... Lumen, 16 ... Balloon, 18 ... Tip tip body, 18a ... Lumen, 36 ... As covering region Extended region, 37 ... stepped portion, 41 ... proximal end side leg region, 42 ... proximal end side cone region, 43 ... straight tube region, 44 ... distal end side cone region, 45 ... distal end side leg region, 47 ... contrast ring, 47a ... end face, 52 ... slit as rigidity-reducing structure, 53 ... tip end region, 61 ... balloon, 71 ... stepped part, 72 ... contrast ring, 72a ... end face, 73 ... step part, 74 ... contrast ring, 74a ... end face 91 ... Balloon, 92 ... Proximal leg region, 93 ... Proximal cone region, 94 ... Straight tube region, 95 ... Distal cone region, 96 ... Distal leg region, 105 ... Stepped portion, 1 8 ... stepped portion, 109 ... contrast ring, 111 ... tapered region.

Claims (13)

An outer tube through which fluid flows through the lumen;
An inner tube that is provided so as to pass through the lumen of the outer tube, is extended to the distal end side than the outer tube, and a guide wire is inserted into the lumen;
A hollow balloon held in a distal end region of the outer tube and an extended region of the inner tube and inflated or deflated by fluid flowing through the lumen of the outer tube;
With
The balloon catheter covered with the balloon in the inner tube is formed so that its rigidity decreases continuously or stepwise from the proximal end side to the distal end side.   The covering region is formed such that the cross-sectional area in the direction perpendicular to the axial direction decreases continuously or stepwise from the base end side to the tip end side, so that the base end side to the tip end side The balloon catheter according to claim 1, wherein the rigidity is lowered continuously or stepwise.   The covering region is formed so that the outer diameter decreases continuously or stepwise from the base end side to the tip end side, so that the cross-sectional area is continuous from the base end side to the tip end side. The balloon catheter according to claim 2, wherein the balloon catheter is reduced in size or stepwise.   4. The balloon catheter according to claim 3, wherein the covering region has a stepped portion formed at an intermediate position in the length direction so that a distal end side has an outer diameter smaller than a proximal end side. The covered region further comprises a contrast body,
The balloon catheter according to claim 4, wherein the contrast body is disposed on a distal end side with respect to the stepped portion.   The balloon catheter according to claim 5, wherein the contrast body is attached with a base end thereof in contact with the stepped portion.   The balloon according to claim 3, wherein the covering region has a tapered region that becomes narrower toward a distal end side, and the outer diameter of the distal end side is smaller than the proximal end side by the tapered region. catheter.   The balloon catheter according to claim 7, wherein the entire covered region is the tapered region. A distal end that has an insertion hole through which the guide wire is inserted, is fixed to the distal end side of the covered region so that the inserted hole communicates with the lumen of the inner tube, and has a lower rigidity than the covered region A chip body,
The balloon catheter according to any one of claims 1 to 8, wherein the balloon is held on the inner tube via the tip part with the tip side fixed to the tip part. .   The balloon catheter according to claim 9, wherein a distal end of the inner tube is located on a proximal end side with respect to a fixing portion between the balloon and the distal tip body. The covered region further comprises a contrast body,
The balloon according to claim 9 or 10, wherein the contrast body is attached such that a tip thereof is brought into contact with a stepped portion generated at a fixing portion between the covering region and the tip part. catheter.   A rigidity reduction structure is provided in the fixed region so that the fixed region fixed to the inner tube in the distal end tip body has a lower rigidity than a region closer to the distal end than the fixed region. The balloon catheter according to claim 9, wherein the balloon catheter is provided. The balloon includes a distal-side fixed region, a distal-side tapered region that is reduced in diameter toward the distal end, a straight tube region that is the largest diameter portion of the balloon when inflated, and a proximal-side tapered region that is reduced in diameter toward the proximal end. And a proximal-side fixing region in this order from the distal end side,
The length dimension along the axial direction of the balloon catheter in the distal end side tapered region is larger than the length dimension along the axial direction of the balloon catheter in the proximal side tapered region. The balloon catheter according to any one of the above.

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