JP2004261299A - Balloon catheter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a balloon catheter with a higher safety which achieves a sufficient joint strength between the inner tube and the tip chip part while achieving the prevention of boring into the wall of the arterial blood vessel. <P>SOLUTION: The balloon catheter 1 includes an outer tube 20 in which a lumen 21 adapted to make fluid pass is formed along the length thereof, an inner tube 30, a tip chip part 40 having an inner layer member 50 joined on the outer circumference at the distal end of the inner tube 30 and an outer layer member 60 with a lower hardness relative to the inner layer member 50 joined on the outer circumference of the inner layer member 50. And the balloon catheter also includes a balloon part 10, in which the outer circumference of the outer tube 20 is joined to the proximal end of the balloon part 10, the inner tube 30 axially penetrates the inside of the balloon 10, the outer circumference of the tip chip part 40 joined to the distal end of the inner tube 30 is joined to the distal end of the balloon part 10, the lumen 21 of the outer tube 20 communicates with the inside of the balloon 10, and the distal end of the tip chip part 40 is positioned on the distal end side of the distal end of the balloon part 10. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a balloon catheter, and more particularly to a balloon catheter suitable as a catheter for intra-aortic balloon pumping (hereinafter referred to as “IABP”).
[0002]
[Prior art]
In order to treat cardiac dysfunction, a balloon catheter is inserted into the aorta, and the aortic balloon pumping method ( The IABP method is known (for example, see Patent Literature 1 and Patent Literature 2).
[0003]
Such a balloon catheter has an outer tube formed with a lumen for flowing a pressure fluid for inflating and deflating the balloon portion, and penetrates the lumen of the outer tube, and is inserted into a patient's artery during insertion. A guide wire is inserted to function as a guide rod, and has an inner tube used to take in blood in the artery and measure arterial pressure when the balloon section is inflated and deflated.
[0004]
The inner tube is required to have a function of supporting the balloon portion to the extent that the balloon portion is not pushed back by the blood flow, and from the viewpoint of ensuring a sufficient flow path cross-sectional area for flowing the pressure fluid, It is required that the diameter be as small as possible. Therefore, the material forming the inner tube is required to have a high flexural modulus. Further, the inner tube is required to have a certain degree of flexibility so that it can be easily inserted into a curved part of a blood vessel.
[0005]
Tubes with high rigidity such as a tube made of a nickel-titanium alloy and a tube made of polyetheretherketone (PEEK) exhibiting superelasticity are known as inner tubes satisfying such characteristics (for example, Patent Document 3 and Patent Document 3). Reference 4).
[0006]
In addition, when inserted into a patient's artery, the distal end of the inner tube has excellent flexibility in order to prevent the above-described rigid inner tube from abutting against the arterial blood vessel wall and perforating it. One in which a tip portion is joined is known (for example, see Patent Document 5).
[0007]
[Patent Document 1]
JP-A-62-114565
[Patent Document 2]
JP-A-63-206255
[Patent Document 3]
JP-A-4-138172
[Patent Document 4]
JP 2001-231865 A
[Patent Document 5]
JP-A-6-114108
[0008]
[Problems to be solved by the invention]
However, the distal end of the inner tube having high rigidity as described above and the tip portion having excellent flexibility have a remarkable difference in hardness, so that the distal end of the inner tube and the distal end of the inner tube have a significant difference. In some cases, it is difficult to obtain sufficient strength for bonding with the tip portion. If the joining strength is not sufficient, the distal tip will fall off from the distal end of the inner tube when inserted into the artery or when the balloon is inflated or deflated, and the dropped distal tip may occlude the artery. In addition, the pressure fluid leaks from the balloon portion, forcing the patient to bear a great burden.
[0009]
On the other hand, in order to obtain sufficient strength for joining between the distal end portion of the inner tube and the distal tip portion, if the hardness of the distal tip portion is increased, the arterial blood, which is the original purpose of the distal tip portion, is increased. Prevention of perforation of the tube wall is not achieved.
[0010]
The present invention has been made in view of the above circumstances, and provides a highly safe balloon catheter in which the joining strength between an inner tube and a distal tip portion is sufficient, and perforation of an arterial blood vessel wall is prevented. With the goal.
[0011]
[Means for Solving the Problems]
The present inventors have conducted intensive studies on the structure of a balloon catheter having a highly rigid inner tube and a highly flexible distal tip portion in order to solve the above problem. The inner layer member joined to the outer periphery of the distal end of the inner layer member, and the outer layer member having a relatively low hardness relative to the inner layer member and joined to the outer periphery of the inner layer member have rigidity. It has been found that it is possible to obtain a balloon catheter with high safety that can secure a sufficient joining strength with the inner tube having a high level, prevent the tip portion from falling off, and prevent perforation of the arterial blood vessel wall during insertion. The present invention has been completed based on the findings.
[0012]
In order to achieve the above object, according to the present invention, an outer tube in which a lumen through which a fluid can flow is formed along a longitudinal direction, and the lumen formed inside the outer tube penetrates in an axial direction. And an inner tube in which the distal end of the inner tube is located on the distal end side of the distal end of the outer tube; and an outer tube joined to the outer periphery of the distal end of the inner tube, and A distal tip portion having an end located on the distal end side of the distal end of the inner tube; and a distal end portion of the outer tube joined to a proximal end portion of a balloon portion, wherein the inner tube is a balloon portion. Penetrates the inside of the inner tube in the axial direction, the outer periphery of the distal tip portion joined to the distal end of the inner tube is joined to the inner periphery of the distal end of the balloon portion, and the lumen of the outer tube and The inside of the balloon section is in communication with the tip section. A balloon portion, the distal end of which is located on the distal end side of the distal end of the balloon portion, wherein the distal tip portion is provided on the outer periphery of the distal end portion of the inner tube. There is provided a balloon catheter having a bonded inner layer member and an outer layer member having a relatively low hardness relative to the inner layer member and bonded to an outer periphery of the inner layer member.
[0013]
It is preferable that the inner layer member is formed so as to become thinner toward the distal end side such that the rigidity of the tip end portion decreases toward the distal end side.
[0014]
It is preferable that a groove is formed on a contact surface of the inner layer member with the outer layer member so that the distal tip portion has a lower rigidity toward a distal end side.
[0015]
The inner layer member preferably has a Shore D hardness of 50 to 85, and the outer layer member preferably has a Shore A hardness of 30 to 95.
[0016]
It is preferable that at least a part of the inner tube is made of an alloy exhibiting superelasticity.
[0017]
It is preferable that the inner tube has a portion at a distal end portion of the inner tube that has relatively low rigidity with respect to other portions of the inner tube.
[0018]
It is more preferable that the distal end of the inner tube is formed to have a relatively small thickness relative to other portions of the inner tube.
[0019]
More preferably, the inner tube is made of an alloy exhibiting superelasticity, and the distal end of the inner tube has a relatively low rigidity with respect to other portions of the inner tube by being heat-treated.
[0020]
More preferably, a slit is formed at the distal end of the inner tube.
[0021]
[Action]
In the balloon catheter of the present invention, the inner layer member joined to the outer periphery of the distal end portion of the inner tube, and the outer layer joined to the outer periphery of the inner layer member have a relatively low hardness relative to the inner layer member. By forming the tip part with the member, the inner layer member with high hardness is joined to the inner tube with high rigidity, so that sufficient joining strength between the tip part and the inner tube can be secured and the tip part falls off In addition, since the outer layer member having low hardness is exposed on the surface side of the distal end tip portion, perforation of the arterial blood vessel wall during insertion is prevented.
[0022]
In the balloon catheter of the present invention, the rigidity of the distal tip portion decreases toward the distal end by forming the thickness of the inner layer member of the distal tip portion so as to become thinner toward the distal end. Since the change in rigidity from the distal end portion to the distal end portion of the inner tube becomes gentle, the insertability into a curved blood vessel can be improved.
[0023]
Further, in the balloon catheter of the present invention, by forming a groove on the contact surface of the inner layer member of the distal tip portion with the outer layer member, the rigidity of the distal end side of the distal tip portion is reduced, and the distal tip portion becomes more flexible. The effect of preventing perforation of the arterial blood vessel wall during insertion can be increased.
[0024]
Furthermore, in the balloon catheter of the present invention, the distal end portion of the inner tube is formed at the distal end portion of the inner tube with a portion having a relatively low rigidity relative to other portions of the inner tube. The change in rigidity at the junction between the tip and the distal end portion is reduced, so that the insertability into a curved blood vessel can be improved.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described based on embodiments shown in the drawings.
[0026]
FIG. 1 is a schematic cross-sectional view of a balloon catheter according to the first to third embodiments of the present invention, and FIGS. 2 to 4 are cross-sectional views of main parts of a distal end portion of the balloon catheter according to the first to third embodiments of the present invention. FIG.
[0027]
As shown in FIG. 1, a balloon catheter 1 according to an embodiment of the present invention is used for a treatment by, for example, the IABP method, and includes a balloon section 10 located at a distal end of the balloon catheter 1, A first lumen 21 through which fluid can flow is formed along the longitudinal direction, and an outer tube 20 joined to the proximal end 14 of the balloon portion 10 and a second lumen 31 are formed along the axial direction. And the inner tube 30 axially penetrating the balloon portion 10 and the first lumen 21 of the outer tube 20, and the distal end of the inner tube 30 which is located at the most distal end of the balloon catheter 1. A tip portion 40 composed of an inner layer member 50 joined to the outer portion and an outer layer member 60 joined to the outer periphery of the inner layer member 50; It is connected to an end portion, and a connector 70 having a first lumen 21 and the communicating the second port 72 through the first port 71 and the outer tube 20 in communication with the second lumen 31 of the inner tube 30.
[0028]
In the balloon catheter 1 configured as described above, a guide wire (not shown) is inserted through the first port 71 of the connector 70 and the second lumen 31 of the inner tube 30, and the balloon portion 10 is moved to a predetermined position in the artery. You will be guided to the location. Then, based on the arterial pressure measured via the second lumen 31 of the inner tube 30, the pressurized fluid is introduced into the balloon section 10 via the second port 72 of the connector 70 and the first lumen 21 of the outer tube 20. The balloon section 10 is inflated and deflated in accordance with the heart beat to assist the heart function.
[0029]
Hereinafter, each component will be described in detail.
[0030]
The balloon portion 10 of the balloon catheter 1 is a tubular body that can be expanded and contracted by a pressurized fluid, and has a distal end side tapered portion 11 extending in a tapered shape toward the distal end side, and a further distal end. A distal end 12 extending to the proximal side, a proximal end taper 13 extending in a tapered shape toward the proximal end, and a proximal end 14 extending further to the proximal end. Have.
[0031]
The outer diameter and length of the balloon section 10 are determined according to the inner volume of the balloon section 10, the inner diameter of the artery, etc., which greatly affect the assisting effect of the cardiac function. For example, when the inner volume of the balloon portion 10 is 30 to 50 cc, the outer diameter is preferably 12 to 16 mm, and the axial length is preferably 190 to 270 mm. The material of the balloon portion 10 is not particularly limited, but is preferably a material having excellent antithrombotic properties and bending fatigue resistance, and is made of, for example, a synthetic resin such as polyurethane or a copolymer of polyurethane and silicon. . The balloon section 10 is formed of a thin film having a thickness of about 50 to 150 μm.
[0032]
A first lumen 21 is formed in the outer tube 20 of the balloon catheter 1 along the axial direction so that a pressure fluid for inflating and deflating the balloon portion 10 flows through the outer tube 20. The inner tube 30 penetrates the first lumen 21 of the outer tube 20 over the entire length, and has a so-called double tube structure. The inner tube 30 extends further from the distal end of the outer tube 20 to the distal end side, penetrates through the inside of the balloon section 10, and the distal end of the inner tube 30 is higher than the distal end of the outer tube 20. It is located on the distal end side.
[0033]
The inner periphery of the proximal end 14 of the balloon portion 10 is joined to the outer periphery of the distal end of the outer tube 20. On the other hand, the inner periphery of the distal end portion 12 of the balloon portion 10 is joined to the outer periphery of the distal end portion of the inner tube 30 with the tip portion 40 interposed therebetween. Examples of these joining methods include heat fusion and adhesion.
[0034]
Accordingly, the first lumen 21 of the outer tube 20 communicates with the inside of the balloon portion 10, and the second lumen 31 of the inner tube 30 opens to the outside at the distal end via the distal tip portion 40. The inside of the first lumen 21 and the balloon portion 10 of the tube 20 does not communicate with the second lumen 31 of the inner tube 30.
[0035]
As a material for forming the outer tube 20 of the balloon catheter 1, for example, a synthetic resin such as polyethylene, polypropylene, polyethylene terephthalate, polyamide, polyvinyl chloride, polyurethane, and fluororesin can be used. The inner diameter and the thickness of the outer tube 20 are not particularly limited. However, from the viewpoint of avoiding complications due to lower limb ischemia and ensuring a sufficient flow path cross-sectional area of the pressure fluid, the inner diameter is 1.5 to 1.5. It is preferably 4.0 mm and the thickness is preferably 0.05 to 0.4 mm. The axial length of the outer tube 20 is usually 300 to 1000 mm.
[0036]
The inner tube 30 of the balloon catheter 1 has a second lumen 31 formed therein along the axial direction, and a guide wire is inserted through the second lumen 31 when the balloon tube 10 is inserted into an artery of a patient, thereby moving the balloon section 10 through the artery. It functions as a guide rod for guiding to a predetermined position in the blood vessel, and is used for taking blood into the artery for measuring arterial pressure. Examples of the material constituting the inner tube 30 include metals such as stainless steel, tungsten, nickel-titanium alloy, and polyetheretherketone (PEEK) having a high flexural modulus and a certain degree of flexibility. It is preferable to use a nickel-titanium alloy exhibiting superelasticity from the viewpoint that it has a higher elastic modulus and is hardly permanently deformed.
[0037]
The inner diameter of the inner tube 30 is not particularly limited as long as the guide wire can be inserted therethrough, but is preferably 0.1 to 1.5 mm, and the wall thickness of the inner tube 30 can support the balloon portion 10. If so, the thickness is not particularly limited, but is preferably 0.05 to 0.4 mm.
[0038]
As shown in FIG. 2, the distal tip section 40 of the balloon catheter 1 has an inner layer member 50 joined to the outer periphery of the distal end of the inner tube 30 described above, and a relatively lower inner layer member 50. And an outer layer member 60 joined to the outer periphery of the inner layer member 50.
[0039]
The material constituting the inner layer member 50 of the tip portion 40 is a synthetic resin such as polyurethane, soft polyvinyl chloride resin, silicone resin, styrene-based elastomer, vinyl chloride-based elastomer, olefin-based elastomer, polyester-based elastomer, and polyamide-based elastomer. Alternatively, natural rubber or the like, preferably having a Shore D hardness of 50 to 85, more preferably about 55 to 70, may be used. When the Shore D hardness is 85 or more, the distal tip portion 40 becomes hard, and there is a possibility that perforation of the arterial blood vessel wall may occur. On the other hand, when the Shore D hardness is 50 or less, the difference in rigidity between the inner layer member 50 and the inner tube 30 joined to the inner layer member 50 increases, and the difference between the inner layer member 50 and the inner tube 30 is increased. There is a tendency that sufficient bonding strength cannot be obtained. Here, the Shore hardness refers to a physical property value measured according to JIS K-7215.
[0040]
The material constituting the outer layer member 60 of the tip portion 40 is a synthetic material such as polyurethane, soft polyvinyl chloride resin, silicone resin, styrene elastomer, vinyl chloride elastomer, olefin elastomer, polyester elastomer, polyamide elastomer, and the like. A resin or natural rubber, preferably having a Shore A hardness of 30 to 95, more preferably a Shore A hardness of about 65 to 80, can be used. When the Shore A hardness is 95 or more, perforation of the arterial blood vessel wall may occur. On the other hand, if the Shore A hardness is 30 or less, it is difficult to synthesize the material.
[0041]
The inner layer member 50 and the outer layer member 60 of the distal tip portion 40 are preferably made of a material having a similar chemical structure from the viewpoint of easy joining of these members, and particularly polyurethane is used from the viewpoint of antithrombotic properties. Is preferred. For example, when polyurethane having a Shore D hardness of about 50 to 85 is used for the inner layer member 50, it is preferable to use polyurethane having a Shore A hardness of about 30 to 95 for the outer layer member 60. In addition, the polyurethane referred to here includes a thermoplastic polyurethane elastomer.
[0042]
As described above, the distal tip portion 40 of the balloon catheter 1 has the inner layer member 50 joined to the outer periphery of the distal end of the inner tube 30 and the inner layer member 50 having relatively low hardness. By forming the outer layer member 60 joined to the outer periphery of the inner layer member 50, the inner layer member 50 having high hardness is joined to the inner tube 30 having high rigidity. A high bonding strength can be ensured, the distal tip portion 40 is prevented from falling off, and the outer layer member 60 having low hardness is exposed on the surface side of the distal tip portion 40, so that the arterial blood vessel wall can be perforated when the balloon catheter 1 is inserted. It can be prevented.
[0043]
As shown in FIG. 2, the outer peripheral surface of the inner layer member 50 of the distal end tip portion 40 has a tapered taper on the distal end side toward the distal end side. On the proximal end side, a convex portion 51 projecting toward the proximal end side so as to enter the inside of the balloon portion 10 is formed. An arterial communication hole 52 penetrating along the axial direction is formed inside the inner layer member 50. Further, as shown in FIG. 2, a groove 53 extending in the circumferential direction is formed on the tapered outer peripheral surface on the distal end side of the inner layer member 50.
[0044]
In addition, on the outer peripheral surface of the outer layer member 60 of the distal end tip portion 40, a substantially shell-like or hemispherical spherical surface is formed on the distal end side to prevent perforation of the arterial blood vessel wall. At the same time, a balloon mounting portion 61 is formed with a step substantially the same as the thickness of the balloon portion 10 toward its proximal end side. In addition, the inside of the outer layer member 60 penetrates along the axial direction so as to substantially coincide with the taper formed on the outer peripheral surface on the distal end side of the inner layer member 50 described above. A tapered through-hole tapering toward.
[0045]
In this manner, by providing the inner layer member 50 and the outer layer member 60 with a taper, the rigidity of the distal tip portion 40 decreases toward the distal end. The change in rigidity toward the tip portion 40 can be moderated. Therefore, when the distal tip portion 40 abuts against the arterial blood vessel wall, the entire distal tip portion 40 is curved so as to follow the shape of the blood vessel wall, so that the insertability of the balloon catheter 1 into the curved blood vessel is improved. Can be. In FIG. 2, the outer peripheral surface on the distal end side of the inner layer member 50 and the inside of the outer layer member 60 are shown as a continuous taper shape. The effect can be achieved.
[0046]
In addition, by forming the groove 34 on the outer peripheral surface on the distal end side of the inner layer member 50 (contact surface with the outer layer member 60), the rigidity on the distal end side of the distal end tip portion 40 is reduced, and the distal end portion 40 becomes flexible. Further, the effect of preventing perforation of the arterial blood vessel wall when the balloon catheter 1 is inserted can be enhanced. In addition, the groove part 53 has a width of 0.05 to 2.0 mm and a depth of 0.05 to 0.5 mm at intervals of 0.05 to 2.0 mm. It is preferable to form by providing. Further, it is preferable to increase the width of the groove or narrow the interval toward the distal end so that the rigidity on the distal end side becomes lower.
[0047]
The distal tip portion 40 has a structure in which the inner layer member 50 is inserted into the through hole of the outer layer member 60 described above, and the outer peripheral surface of the inner layer member 50 and the inner peripheral surface of the outer layer member 60 are joined. The tip portion 40 having such a structure is formed by separately molding the inner layer member 50 and the outer layer member 60 by a method such as an injection molding method, and then joining the inner layer member 50 and the outer layer member 60 by a method such as welding with a solvent, heat fusion, or bonding. And it can also be obtained by integrally molding using a two-color molding method or the like.
[0048]
In configuring the balloon catheter 1, the inner periphery of the distal end portion 12 of the balloon portion 10 is joined to the balloon mounting portion 61 of the outer layer member 60 of the distal tip portion 40 by a method such as heat fusion or adhesion. Is done. Further, the distal end of the inner tube 30 is inserted into the arterial communication hole 52 of the inner peripheral member 50 from the proximal end side, and is joined by a method such as adhesion. The adhesive used for bonding the inner layer member 50 and the inner tube 30 is not particularly limited, but it is preferable to use an epoxy-based adhesive.
[0049]
The entire axial length L2 of the tip portion 40 is 8 to 25 mm, and the axial length L3 of the convex portion 51 of the inner layer member 50 is 20 to 80% of the length L2. , More preferably 30 to 70%. The length L4 of the balloon mounting portion 61 is approximately 3 to 8 mm, and the distance L5 from the distal end of the distal tip portion 40 to the distal end of the inner tube 30 is approximately 3 to 15 mm.
[0050]
Further, the maximum outer diameter of the distal tip portion 40 is 1.6 to 3.4 mm, and the outer diameter of the convex portion 51 of the inner layer member 50 is 50 to 90% of the maximum outer diameter of the distal tip portion 40, preferably 65-85%. Further, the inner diameter of the distal end of the arterial communication hole 52 of the inner layer member 50 of the distal tip portion 40 is not particularly limited, but is usually 0.1 to 1.5 mm.
[0051]
In this way, the distal end of the inner tube 30 enters the arterial communication hole 52 of the inner layer member 50 of the distal tip portion 40 such that the distal end of the inner tube 30 is located closer to the proximal end by the distance L5 than the distal end of the distal tip portion 40. With such a structure, the distal end of the inner tube 30 does not hit the wall of the arterial blood vessel when the balloon catheter 1 is inserted, so that a perforation does not occur. Further, by forming the convex portion 51 that is not restrained with respect to the balloon portion 10 on the inner layer member 50 of the distal tip portion 40, the distal end of the inner tube 30 is connected to the distal end of the distal tip portion 40 as described above. The structure located on the more proximal end side can be easily adopted.
[0052]
Although not specifically shown, the distal tip portion 40 is formed by mixing an X-ray contrast material into a material or forming a portion that is impermeable to X-rays by an embedding method or the like, and inserting the balloon catheter 1 into an artery. By observing the distal tip portion 40 from outside the body by X-ray fluoroscopy, the balloon portion 10 of the balloon catheter 1 may be guided to an accurate position in the artery. Examples of the X-ray contrast material include metal particles such as gold, platinum, tungsten, and lead, and metal compounds such as titanium oxide, barium sulfate, bismuth trioxide, and bismuth subcarbonate.
[0053]
Further, in the first embodiment of the present invention, as shown in FIG. 2, a tapered low-rigid portion 32 tapering toward the distal end is formed at the distal end of the inner tube 30. In addition, by making the low-rigidity portion 32 relatively thin with respect to the other portions of the inner tube 30, the rigidity is relatively low with respect to the other portions of the inner tube 30. For example, when the thickness of the inner tube 30 other than the low-rigidity portion 32 is set to 100%, the thickness of the low-rigidity portion 32 is preferably set to about 30 to 70%. The distance L1 from the distal end of the inner tube 30 where the low-rigidity portion 32 is formed is preferably 5 to 15 cm.
[0054]
As a means for setting only the low-rigidity portion 32 of the inner tube 30 to be thin, means such as chemical polishing, electric field polishing, and mechanical polishing can be exemplified. For example, when performing by chemical polishing, it can be formed by immersing only the low-rigidity portion 32 of the inner tube 30 in an etchant such as nitric acid and pulling up the inner tube 30 at a constant speed.
[0055]
As a second embodiment of the low-rigidity portion 32 formed at the distal end of the inner tube 30, as shown in FIG. 3, the inner tube 30 is made of an alloy such as a nickel-titanium alloy exhibiting superelasticity, By subjecting the distal end of the inner tube 30 to heat treatment, the low-rigidity portion 32 can be formed. When the rigidity of the portion other than the low-rigidity portion 32 of the inner tube 30 in the second embodiment is set to 100%, it is preferable that the low-rigidity portion 32 is set to have a rigidity of 10 to 60%. When the rigidity of the low-rigidity portion 32 is 10% or less of the rigidity of the other portions, the guide rod when the balloon catheter 1 is inserted is too soft, and when it is 60% or more, the effect of improving the insertability is improved. Few. As a method of this heat treatment, for example, a method of performing a baking heat treatment at 300 to 500 ° C. on the distal end portion of the inner tube 30 is given.
[0056]
As shown in FIG. 4, as a third embodiment of the low-rigidity portion 32 of the inner tube 30, the low-rigidity portion 32 is formed by forming a spiral slit 33 at the distal end of the inner tube 30. You can also. The slit 33 is set such that the width of the slit 33 increases or the interval between the slits 33 decreases toward the distal end so that the rigidity of the inner tube 30 decreases toward the distal end. Is preferred.
[0057]
In the balloon catheter 1 according to the embodiment of the present invention, as described above, the portion of the distal end of the inner tube 30 having a relatively low rigidity relative to the other portions of the inner tube 30 (the low-rigidity portion 32). Is formed, the change in rigidity at the junction between the distal end portion of the inner tube 30 and the distal tip portion 40 is reduced, so that when the balloon catheter 1 is inserted, the distal tip portion 40 abuts against the arterial blood vessel wall. At this time, the distal tip portion 40 can be prevented from bending at the joint with the inner tube 30, so that the insertability into a curved blood vessel is improved.
[0058]
In the first embodiment of the present invention, the tapered shape of the distal end of the low-rigidity portion 32 of the inner tube 30 is substantially the same as that of the distal end of the arterial communication hole 52 of the inner layer member 50 of the distal tip portion 40. Since the taper is formed so as to coincide with each other, no step is formed between the inner peripheral surface of the arterial communication hole 52 and the inner peripheral surface of the distal end of the inner tube 30. On the other hand, in the second and third embodiments, the proximal end of the arterial communication hole 52 of the inner layer member 50 is expanded to substantially the same diameter as the outer diameter of the inner tube 30, and the arterial communication hole 52 is No step is formed between the inner peripheral surface of the inner tube 30 and the inner peripheral surface of the distal end of the inner tube 30.
[0059]
As shown in FIG. 1, the connector 70 installed outside the patient is connected to the proximal end of the inner tube 30 and the proximal end of the outer tube 20, and is connected to the second lumen 31 of the inner tube 30. It has a first port 71 communicating with the first tube 71 and a second port 72 communicating with the first lumen 21 of the outer tube 20.
[0060]
When the balloon portion 10 is guided to a predetermined position in the artery by the guide wire via the first port 71 of the connector 70, a blood pressure measurement device (not shown) is connected to the first port 71, and the distal tip portion Blood in the artery is taken in from the arterial communication hole 52 formed in the inner tube 30 through the second lumen 31 of the inner tube 30, and the arterial pressure is measured.
[0061]
Then, a pump device (not shown) is connected to the second port 72 of the connector 70, and a pressurized fluid such as helium gas is introduced or drawn into the balloon portion 10 through the first lumen 21 of the outer tube 20. The pump device is controlled in accordance with the heart beat measured by the arterial pressure measurement, and the balloon unit 10 is inflated and deflated to assist the heart function.
[0062]
The embodiments described above are described for facilitating the understanding of the present invention, but are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention. For example, it is not always necessary to form a taper or a groove in the inner layer member and the outer layer member of the tip portion, and the above-described embodiments of the inner tube may be used in combination.
[0063]
【Example】
Hereinafter, the effects of the present invention were confirmed by Examples and Comparative Examples that further embody the present invention.
[0064]
Example 1
As the inner tube, a nickel-titanium alloy tube having an outer diameter of 1.0 mm and a wall thickness of 100 μm having a distal end portion subjected to heat treatment as in the above-described second embodiment is used as an inner layer member of the tip portion, Injection molded polyurethane (trade name: Tecoflex EG-60D-B40, manufactured by Thermedics) containing barium sulfate having a Shore D hardness of 65. Polyurethane blended with barium sulfate having a Shore A hardness of 78 in the outer layer member (trade name) : Tecoflex EG-80A-B40, manufactured by Thermics Co., Ltd.) is used, and the inner layer member and the outer layer member are welded with tetrahydrofuran to form a tip portion, and then 8 mm from the distal end of the inner tube. Sample with the distal end up to the distal end inserted into the arterial communication hole of the tip and glued with epoxy adhesive 30 pieces were produced.
[0065]
Comparative Example 1
Thirty samples similar to Example 1 except that the tip portion was integrally injection-molded with polyurethane (trade name: Tecoflex EG-80A-B40, manufactured by Thermodics) containing barium sulfate having a Shore A hardness of 78. Produced.
[0066]
Evaluation
The bonding strength was evaluated for each sample composed of the manufactured inner tube and the tip portion.
[0067]
The evaluation of the bonding strength was performed by fixing the proximal end of the inner tube, pulling the distal tip toward the distal end at a speed of 100 mm / sec, and pulling the tip when the distal tip came off the inner tube. Was measured.
[0068]
In the evaluation of the bonding strength, each sample of Example 1 had a tensile force of 29.4 to 39.2 N (average: 32.3 N), whereas each sample of Comparative Example 1 had a tensile force. It was 3.9-5.9 N (average: 4.9 N). Therefore, if the distal tip portion is formed only of a material having low hardness, the joining strength between the distal tip portion and the inner tube cannot be sufficiently obtained, but the distal tip portion is bonded to the inner tube as in the sample of Example 1. It was confirmed that the joining strength between the inner tube and the distal tip portion was improved by making the inner layer member of the distal tip portion high in hardness.
[0069]
【The invention's effect】
As described above, according to the present invention, the distal tip portion of the balloon catheter has an inner layer member joined to the outer periphery of the distal end of the inner tube, and has a relatively low hardness relative to the inner layer member. By forming the outer layer member joined to the outer periphery of the inner layer member, the inner layer member having high hardness is joined to the inner tube having high rigidity, so that the distal tip portion and the inner tube are sufficiently joined. The strength can be secured, the tip portion is prevented from falling off, and the outer layer member of low hardness is exposed on the surface side of the tip portion, so that the perforation of the arterial blood vessel wall at the time of insertion is prevented.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of a balloon catheter according to first to third embodiments of the present invention.
FIG. 2 is a cross-sectional view of a main part of a distal end portion of the balloon catheter according to the first embodiment of the present invention.
FIG. 3 is a sectional view of a main part of a distal end portion of a balloon catheter according to a second embodiment of the present invention.
FIG. 4 is a sectional view of a main part of a distal end portion of a balloon catheter according to a third embodiment of the present invention.
[Explanation of symbols]
1. Balloon catheter
10. Balloon section
11 ... distal end taper
12 ... distal end
13 ... Proximal end taper
14 ... Proximal end
20 ... Outer tube
21 ... 1st lumen
30 ... Inner tube
31 ... second lumen
32: Low rigidity part
33 ... Slit
40: Tip section
50 ... Inner layer member
51 ... convex part
52 ... arterial communication hole
53 ... groove
60 ... outer layer member
61 Balloon mounting part
70… Connector
71 ... 1st port
72 ... second port

Claims (9)

An outer tube in which a lumen through which fluid can flow is formed along the longitudinal direction,
An inner tube penetrating the lumen formed inside the outer tube in the axial direction, wherein a distal end of the inner tube is located on a distal end side of a distal end of the outer tube;
A distal tip portion joined to the outer periphery of the distal end portion of the inner tube, the distal end of the distal tip portion being located on the distal end side of the distal end of the inner tube;
A distal end of the outer tube joined to a proximal end of a balloon portion, the inner tube extending axially through the inside of the balloon portion, and the tip tip joined to a distal end of the inner tube; The outer periphery of the portion is joined to the inner periphery of the distal end of the balloon portion so that the lumen of the outer tube communicates with the inside of the balloon portion, and the distal end of the distal tip portion is remote from the balloon portion. A balloon portion located on the distal end side of the distal end,
The tip section,
An inner layer member joined to the outer periphery of the distal end of the inner tube,
An outer layer member having a relatively low hardness relative to the inner layer member and being joined to an outer periphery of the inner layer member. The balloon catheter according to claim 1, wherein the inner layer member is formed so as to be thinner toward the distal end side so that the distal tip portion has a lower rigidity toward the distal end side. . 3. The balloon catheter according to claim 1, wherein a groove is formed in a contact surface of the inner layer member with the outer layer member such that the distal tip portion has a lower rigidity toward a distal end side. 4. The balloon catheter according to any one of claims 1 to 3, wherein the inner layer member has a Shore D hardness of 50 to 85, and the outer layer member has a Shore A hardness of 30 to 95. The balloon catheter according to any one of claims 1 to 4, wherein at least a part of the inner tube is made of an alloy exhibiting superelasticity. The balloon catheter according to any one of claims 1 to 5, wherein the inner tube has, at a distal end portion of the inner tube, a portion having relatively low rigidity with respect to other portions of the inner tube. 7. The balloon catheter according to claim 6, wherein the distal end of the inner tube is formed to be thinner relatively than other portions of the inner tube. 7. The inner tube according to claim 6, wherein the inner tube is made of an alloy exhibiting superelasticity, and a distal end portion of the inner tube is heat-treated so as to have a relatively low rigidity with respect to other portions of the inner tube. Balloon catheter. The balloon catheter according to claim 6, wherein a slit is formed at a distal end of the inner tube.

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