JP2002291899A - Balloon catheter and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a balloon catheter that flexibly deforms in response to a bending portion of a blood vessel and has especially a good insertion characteristic and a good push characteristic. SOLUTION: The balloon catheter 2 has an external tube 6 in which at least one balloon expansion lumen 24 or 10 is formed in the longitudinal direction, and a cylindrical portion 4a having a larger external diameter than the external tube 6 in an inflated state. A proximal end sealing portion 5 integrally formed in the proximal end of the cylindrical portion 4a and having a smaller outside diameter than the cylindrical portion 4a has a jointed portion 5a that is duplicately jointed to the distal end of the external tube 6, and a non-jointed portion 5b having an external diameter nearly equal to the jointed portion 5a and not overlapping the distal end of the external tube 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balloon catheter and a method of manufacturing the same, and more particularly, to a balloon catheter suitably used as, for example, a vascular dilatation balloon catheter and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, medical technology has tended to move toward minimally invasive treatment. For example, stenosis of the coronary arteries is increasingly being treated with a vasodilating balloon catheter, replacing previous coronary artery bypass surgery. This method of treatment is becoming increasingly applicable in order to greatly reduce the burden on the patient, together with its economic advantages.
At the same time, there is a need for a more efficient and simple structure of a balloon catheter used for simple dilation of coronary stenosis.

[0003] In order to treat a stenosis in a blood vessel, the stenosis is inserted into the blood vessel, the balloon is inflated to expand the stenosis, and the blood flow on the peripheral side of the stenosis is improved.
As a so-called PTCA balloon catheter, an over-the-wire balloon catheter and a monorail balloon catheter (for example, JP-A-2000-21)
7923). In any of these types of balloon catheters, a guide wire is first passed through the stenosis in the blood vessel, and then the balloon catheter is sent to the stenosis along the guide wire, and the balloon is inflated to inflate the stenosis. To expand.

In a conventional balloon catheter including such a PTCA balloon catheter, a proximal end of a balloon portion is attached to an outer periphery of a distal end of a catheter tube with an adhesive or the like. At the time of attachment, in order to firmly fix the balloon portion to the distal end portion of the catheter tube, the distal end of the catheter tube is overlapped and joined to a position where the balloon portion bulges up.

[0005]

However, balloon catheters used for applications such as PTCA are used for thin blood vessels having a large number of bifurcations such as coronary arteries.
If the distal end of the catheter tube is overlapped and joined to the point where the balloon section bulges up, it may be difficult to deform flexibly corresponding to the bent part of the blood vessel. In the vicinity of the position end, structural improvement has been required.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide a balloon catheter which deforms flexibly in response to a bent portion of a blood vessel and has particularly excellent insertion characteristics and push-in characteristics, and its manufacture. Is to provide a way.

[0007]

In order to achieve the above object, a balloon catheter according to the present invention comprises a catheter tube in which at least one lumen for balloon expansion is formed along a longitudinal direction, and a balloon catheter in an inflated state. A tubular portion having an outer diameter greater than the outer diameter of the catheter tube; and a distal end seal integrally formed at the distal end of the tubular portion and having an outer diameter smaller than the tubular portion. A balloon catheter comprising: a balloon portion having a portion and a proximal end sealing portion integrally formed at a proximal end of the tubular portion and having a smaller outer diameter than the tubular portion. A joining portion where the proximal end sealing portion overlaps and is joined to a distal end portion of the catheter tube, and has a substantially same outer diameter as the joining portion, and overlaps with a distal end portion of the catheter tube. Not non-contact And having a portion.

Preferably, in the proximal end sealing portion of the balloon portion, the ratio of the axial length of the joined portion to the axial length of the non-joined portion is 1: 1 to 1:10, more preferably. Is in the range of 1: 2 to 1: 5.

[0009] Preferably, a joint portion at a proximal end sealing portion of the balloon portion is heat-fused to a distal end portion of the catheter tube.

A method of manufacturing a balloon catheter according to the present invention includes the steps of inserting a mandrel into the distal end of a catheter tube, and sealing the proximal end sealing portion of the balloon around the distal end of the catheter tube. Step of overlapping the joining portion, and covering the outer periphery of the joining portion with a heat-resistant film, and heating the heat-resistant film to heat-bond the joining portion to the distal end of the catheter tube. Having.

[0011]

In the balloon catheter according to the present invention, the proximal end sealing portion of the balloon portion has a joint portion overlapped and joined to the distal end portion of the catheter tube, and a catheter having substantially the same outer diameter as the joint portion. A non-overlapping unjoined portion at the distal end of the tube. The non-joined portion of the balloon portion at the proximal end sealing portion is a portion that hardly contributes to the therapeutic effect due to the expansion of the balloon portion. I do.

Therefore, even when the balloon catheter of the present invention is inserted into a thin blood vessel having many branches such as a coronary artery, the distal end of the balloon catheter is flexibly deformed corresponding to the bent part of the blood vessel. . That is, in the balloon catheter of the present invention, the insertion characteristics and the pushing characteristics of the balloon catheter are improved.

In the method for manufacturing a balloon catheter according to the present invention, the balloon catheter according to the present invention can be manufactured relatively easily, and the bonding between the balloon portion and the catheter tube becomes strong.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the drawings. The balloon catheter 2 according to the present embodiment shown in FIG. 1 is used for methods such as percutaneous coronary angioplasty (PTCA), dilation of a blood vessel such as a limb, dilation of an upper ureter, and renal vasodilation. It is used to dilate a stenosis formed in a blood vessel or other body cavity. In the following description, a case where the balloon catheter 2 of the present embodiment is used for PTCA will be described as an example.

The balloon catheter 2 for expansion according to the present embodiment
Is a so-called monorail type balloon catheter, which has a balloon portion 4, an outer tube 6 as a catheter tube, an inner tube 12, and a connector 8.

The balloon portion 4 shown in FIGS. 1 and 4 has a tubular portion 4a having an outer diameter larger than the outer diameter of the outer tube 6 in an expanded state. At both ends of the cylindrical portion 4a,
Contiguous tapered reduced diameter portions 4b and 4c and a proximal end sealing portion 5 and a distal end sealing portion 7 respectively following them are integrally formed. Proximal end seal 5
Has a smaller outer diameter than the tubular portion 4a so as to be connected to the outer peripheral portion of the distal end of the outer tube 6. Also, the distal end sealing portion 7 has a smaller outer diameter than the proximal end sealing portion 5 so as to be connected to the outer peripheral portion of the distal end of the inner tube 12.

The thickness of the balloon 4 is not particularly limited, but is 15 to 300 μm, preferably 30 to 150 μm. If the cylindrical portion 4a of the balloon portion 4 is cylindrical,
The shape is not particularly limited, and may be a cylinder or a polygonal cylinder. The outer diameter of the balloon portion 4 at the time of expansion is determined by factors such as the inner diameter of a blood vessel, and is usually about 1.5 to 10.0 mm, preferably 3 to 7 mm. This balloon part 4
The axial length of the cylindrical portion 4a is determined by factors such as the size of the intravascular stenosis, and is not particularly limited, but is 15 to 50 mm, preferably 20 to 40 mm. The balloon portion 4 before being expanded is folded and wound around the inner tube 12, and has an outer diameter as small as possible.

The material forming the balloon portion 4 is preferably a material having a certain degree of flexibility. For example, ethylene and other α-olefins such as polyethylene, polyethylene terephthalate, polypropylene and ethylene-propylene copolymer are used. Copolymer, ethylene-vinyl acetate copolymer, polyvinyl chloride (PVC), cross-linked ethylene-vinyl acetate copolymer, polyurethane, polyamide,
Polyamide elastomer, polyimide, polyimide elastomer, silicone rubber, natural rubber, etc. can be used,
Preferred are polyethylene, polyethylene terephthalate and polyamide. The balloon portion 4 is made of a material and thickness that is more flexible than the tubes 6 and 12, so that the balloon portion 4 can expand and contract when a fluid is introduced therein.

As shown in FIG. 4, the proximal end sealing portion 5 of the balloon portion 4 has a joint portion 5a overlapped and joined to the distal end of the outer tube 6, and an outer portion substantially the same as the joint portion 5a. A non-joining portion 5b having a diameter and not overlapping the distal end of the outer tube 6 is provided. The joint portion 5a is joined to the outer periphery of the distal end portion of the outer tube 6 by means such as heat fusion or adhesion, and the first lumen 10 of the outer tube 6 communicates with the internal expansion space of the balloon portion 4. It has become. The distal end sealing portion 7 of the balloon portion 4 is joined to the outer periphery of the distal end portion of the inner tube 14 by means such as heat fusion or adhesion, and the internal expansion space of the balloon portion 4 is 1 lumen 1
If it is not 0, it is sealed to the outside. Outer tube 6
The first lumen 10 is a passage for sending a fluid into the internal expansion space of the balloon portion 4 to expand the balloon portion 4 or to extract the fluid from the expansion space of the balloon portion 4 and to contract the balloon portion 4. .

In the present embodiment, in the proximal end sealing portion 5 of the balloon portion 4, the axial length La of the joining portion 5a and
Ratio of the non-joined portion 5b to the axial length Lb (La: Lb)
However, 1: 1 to 1:10, more preferably 1: 2
It is in the range of 1: 5. Axial length La of joint portion 5a
Is preferably 2 to 5 mm. In addition, the non-joined portion 5b
Is preferably 15 to 20 mm.
If the axial length La of the joining portion 5a is too short, the joining tends to be insufficient, and if it is too long, the length of the overlapping portion tends to be long, and the flexibility at that portion tends to decrease.
Further, if the axial length Lb of the non-joined portion 5b is too short,
It tends to have the same disadvantages as the conventional balloon catheter. If it is too long, the strength of the balloon portion 4 tends to decrease. In addition, the total length Lc of the proximal end sealing portion 5 is preferably 17 to 25 mm.

As shown in FIG. 4, the inner tube 12 extends coaxially and axially in the expansion space of the balloon portion 4 and the inside of the first lumen 10 on the distal end side of the outer tube 6, and has a so-called coaxial catheter. It has a tube structure. A contrast ring 15 is attached to the outer periphery of the inner tube 12 located inside the balloon portion 4. When the balloon catheter 2 is inserted into a living body, the position of the contrast ring 15 is detected by X-rays or the like from outside the living body. Imaging is possible. Examples of the material of the contrast ring 15 include metals such as gold, platinum, and tungsten.

A second lumen 14 is formed inside the inner tube 12, and has a distal end opening 20 opening at the distal end sealing portion 7 of the balloon portion 4. The proximal end opening 22 of the inner tube 12 is opened to the outside through a through-hole 21 of a tube wall located in the middle of the outer tube 6 in the longitudinal direction. The periphery of the proximal end opening 22 of the inner tube 12 and the periphery of the through hole 21 in the tube wall of the outer tube 6 are hermetically joined by a heat fusion method. The shape of the proximal end opening 22 of the inner tube 12 is not particularly limited,
Although various shapes such as a circular shape and an elliptical shape can be adopted, in the present embodiment, the inner tube 12 has an elliptical shape obtained by diagonally cutting the open end. The second lumen 14 of the inner tube 12 is a guidewire insertion lumen through which a guidewire 42 shown in FIG. 4 for guiding the balloon catheter 2 into a body cavity is inserted. The guide wire 42 is made of, for example, a single wire or a stranded wire such as stainless steel, copper, a copper alloy, titanium, and a titanium alloy. Preferably it is 0.25-0.6 mm.

In the present embodiment, the outer tube 6 includes a first outer tube member 6a having a circular cross section and a second outer tube member 6b having a modified cross section joined to the proximal end of the first outer tube member 6a. And the proximal end opening 2 of the inner tube 12
2 is opened to the outside through a tube wall located in the longitudinal direction of the first outer tube member 6a. The axial length L2 of the first outer tube 6a is not particularly limited, but is preferably 100 to 400 mm, and more preferably 200 to 300 mm.

The first outer tube member 6a may be made of, for example, the same material as the balloon portion 4, but is preferably made of a material having flexibility, for example, polyethylene, polyethylene terephthalate, polypropylene, ethylene-ethylene. Uses propylene copolymer, ethylene-vinyl acetate copolymer, polyvinyl chloride (PVC), cross-linked ethylene-vinyl acetate copolymer, polyurethane, polyamide, polyamide elastomer, polyimide, polyimide elastomer, silicone rubber, natural rubber, etc. Preferably, it is made of polyethylene, polyamide, or polyimide.

The soft synthetic resin constituting the first outer tube member 6a is preferably a polyurethane, polyamide, polyimide, polyethylene or the like having a JIS hardness of 50.
About A to 90 A can be used.

The inner tube 12 can be made of a soft synthetic resin of the same material as the first outer tube 6a.
The first outer tube 6a may be made of a synthetic resin that is harder than the first outer tube 6a. The position where the proximal end opening 22 of the inner tube 12 opens outside the first outer tube member 6a is preferably a position of a length L1 from the distal end of the first outer tube member 6a, and the length L1 Is preferably 150 to 350 mm, more preferably 200 to 300 mm. Also, the first
The outer diameter of the outer tube member 6a is not particularly limited, but is preferably 0.5 to 5 mm, and more preferably 0.5 to 1 mm.
mm. The thickness of the first outer tube member 6a is not particularly limited, but is preferably 0.05 to 0.5 mm, and more preferably 0.1 to 0.2 mm.

The outer diameter of the inner tube 12 is determined so that a gap is formed between the inner tube 12 and the first outer tube member 6a, and is not particularly limited, but is preferably 0.3 to 3 mm, more preferably 0.3 to 3 mm. 0.8 mm. Inner tube 12
Is not particularly limited as long as it can penetrate the guide wire 42, and is, for example, 0.15 to 1.0 mm, and preferably 0.25 to 0.6 mm.

The second outer tube member 6b may be made of the same material as the first outer tube member 6a, but is preferably made of another material. For example, the first outer tube member 6a is preferably made of a synthetic resin that is softer than the second outer tube member 6b.

As the soft synthetic resin constituting the first outer tube member 6a, preferably, a JIS hardness of 50 such as polyurethane, polyamide, polyimide, polyethylene or the like is used.
About A to 90A can be used, and as the hard synthetic resin constituting the second outer tube member 6b, those having a JIS hardness of 50D to 75D such as polyurethane, polyamide, polyimide, and polyethylene can be used. .

In this embodiment, as shown in FIG. 2B, the outer shape of the cross section of the second outer tube member 6b has an elliptical shape elongated in the Y-axis direction. The ratio of the maximum cross-sectional width xm of the catheter tube in the X-axis direction perpendicular to the Y-axis to the maximum cross-sectional width ym in the Y-axis direction (x
m / ym) is in the range of 0.8 to 0.1, and the third lumen 24 having a semicircular cross section and the fourth lumen 2 having a circular cross section are provided.
6 are formed separately along the Y-axis direction.

The semicircular cross-sectional area of the third lumen 24 is
It is sufficient that the cross-sectional area is sufficient to allow the balloon expansion pressure fluid to flow, and is not particularly limited.
08 to 0.20 mm ² . Also, the fourth lumen 2
The circular cross-sectional area of No. ⁶ is not particularly limited as long as it is a sufficient area for inserting the reinforcing rod 28 therein, but is preferably 0.05 to 0.5 mm ² , and more preferably 0.1 to 0.5 mm ² . 0.2 mm ² .

In this embodiment, the second outer tube member 6b
, The maximum cross-sectional width ym in the Y-axis direction is 0.6
It is preferably about 1.2 mm. Second outer tube member 6b
Is joined to the proximal end of the first outer tube member 6a having a circular cross section, so that the cross-sectional shape near the joint 9 is the same as the circular cross-sectional shape with the first outer tube member 6a. In order to make them coincide with each other, the cross-sectional shape gradually changes from the deformed cross section to the circular cross section toward the joint 9.

The third lumen 24 formed along the longitudinal direction of the second outer tube member 6b communicates with the first lumen 10 of the first outer tube member 6a, and through these, the expansion space of the balloon portion 4. To take fluid in and out. The fourth lumen 26 of the second outer tube 6b is a lumen for inserting the reinforcing rod 28 and communicates with the first lumen 10 of the first outer tube member 6a. It is closed at 8 and does not allow fluid to enter or exit. The connector 8 is connected to the proximal end of the second outer tube member 6b, and has a port formed to communicate with the third lumen 24 of the second outer tube 6b. The port is a portion through which the pressurized fluid flows in and out, and does not communicate with the fourth lumen 26.

FIGS. 1, 2A-2C and 3
Is inserted over the entire length inside the fourth lumen 26 of the second outer tube member 6b, and the distal end thereof passes over the joint 9 with the first outer tube member 6a. It protrudes into the first lumen 10 of the first outer tube member 6a. The proximal end of the reinforcing rod 28 has a circular cross-section, tapers in the middle toward the distal end, and gradually has a cross-sectional shape at the distal end so as to have a flat cross-section. Has changed. As shown in FIGS. 1 and 4, the distal end portion 28a of the reinforcing rod 28 having a flat cross section slightly exceeds the proximal end opening portion 22 of the inner tube 12 (preferably about L3 = 1 to 10 cm). And the distal end 2a thereof is not fixed to the inner wall of the first outer tube member 6a.

In the present embodiment, the proximal end of the reinforcing rod 28 is inserted over the entire length into the fourth lumen 26 of the second outer tube member 6b, and a predetermined length L from the proximal end.
In the range of 5, it is fixed to the inner wall of the fourth lumen 26 by an adhesive. That is, in the present embodiment, the reinforcing rod 28 is not fixed to the inner wall of the fourth lumen 26 on the distal end side from the position of the predetermined length L4 from the tube joining portion 9 and the first outer tube member 6a It is not fixed to the inner wall of the first lumen 10. Predetermined length L4
And L5 are not particularly limited, but preferably L4 =
50 to 150 mm, preferably L5 = 1000 to 1
500 mm.

The maximum outer diameter of the reinforcing rod 28 is the second
It is determined so that it can be inserted into the fourth lumen 26 of the outer tube member 6b, and is not particularly limited.
０．６0.6 mm. The reinforcing rod 28 is made of a metal material such as stainless steel, copper, copper alloy, titanium, and titanium alloy;
Alternatively, it is made of a synthetic resin such as polyimide, polyamide, or polyethylene terephthalate.

The pressure fluid introduced into the first lumen 10 through the port of the connector 8 is not particularly limited, but may be, for example, a radiopaque medium and a physiological saline solution.
A 0/50 mixed aqueous solution is used. The reason for including the radiopaque medium is to image the positions of the balloon portion 4 and the outer tube 6 using radiation when the balloon catheter 2 is used. The pressure of the pressure fluid for inflating the balloon portion 4 is not particularly limited, but is about 3 to 12 atm, preferably about 4 to 18 atm in absolute pressure.

In this embodiment, the first outer tube member 6a
It is preferable that the outer periphery of the outer tube 6 composed of the first outer tube member 6b and the second outer tube member 6b is coated with a coating material made of a hydrophilic polymer substance having lubricity in a wet state. By covering the outer periphery of the outer tube 6 with such a covering material, it is possible to reduce insertion resistance when the balloon catheter 2 is inserted into a blood vessel or the like. The outer periphery of the balloon 4 may be covered with a coating material. However, the balloon portion 4 expands a stenotic portion such as a blood vessel. When the stenotic portion is expanded, the balloon portion slides on the stenotic portion. Is not always preferred. Therefore, in the present embodiment, only the outer periphery of the outer tube 6 is covered with a coating material made of a hydrophilic polymer substance.

As the hydrophilic polymer, there are a natural polymer and a synthetic polymer. Examples of natural polymers include starch, cellulose, tannin / nignin, polysaccharide, and protein. Synthetic polymers include PVA, polyethylene oxide, acrylic acid, maleic anhydride,
Examples include phthalic acid-based, water-soluble polyester, ketone aldehyde resin, (meth) acrylamide-based, vinyl heterocyclic, polyamine-based, polyelectrolyte, water-soluble nylon-based, and glycidyl acrylate-based.

Among these, hydrophilic polymer substances that can be suitably used as a coating material for the outer tube 6 include, in particular, cellulosic polymer substances (eg, hydroxypropyl cellulose) and polyethylene oxide polymer substances (eg, Polyethylene glycol), maleic anhydride-based polymer (for example, maleic anhydride copolymer such as methyl vinyl ether-maleic anhydride copolymer), acrylamide-based polymer (for example, polydimethylacrylamide), water-soluble nylon (for example, Toray) AQ-nylon P-70) or a derivative thereof is preferred because a low coefficient of friction can be stably obtained.

Next, a method for manufacturing the balloon catheter 2 according to this embodiment will be described. First, the balloon part 4 shown in FIG. 4 is formed. When forming the balloon portion 4, first, as shown in FIG. 5, a mandrel 30 is used, and the balloon membrane proximal end forming portion 30 a of the mandrel 30 faces downward, and the balloon membrane distal end forming portion faces upward,
Dipping into the solvent solution 32 from the proximal end forming portion 30a,
Pull up from the distal end forming portion 30b.

By making the lifting speed lower than the descent speed for immersion, the outer periphery of the mandrel 30 has a proximal end forming portion 30a as compared with the distal end forming portion 30b.
A thick solution layer is formed on the side. The descent speed is not particularly limited, but is, for example, about 5 to 15 mm / sec.
The lifting speed is preferably as low as approximately 1/5 to 1/15 of the lowering speed. At such a speed ratio, the mandrel 3
0 is completely immersed in the solvent solution 32 and then pulled up, so that a thick solution layer is formed on the outer periphery of the mandrel 30 on the side of the proximal end forming portion 30a. Thereafter, the outer peripheral surface of the mandrel 30 is dried by air drying, and then, if necessary, the immersion, lifting and drying steps are repeated several cycles. Thereafter, after sufficient drying, the mandrel is pulled out, so that a cylindrical balloon membrane that is thicker at the proximal end side than at the distal end side of the balloon portion 4 can be obtained.

The thermoplastic resin in the solution 32 is not particularly limited, but examples thereof include a vinyl chloride resin, a urethane resin, an amide resin, an olefin resin, and an imide resin. Among them, urethane resins having excellent flex fatigue resistance are preferable.

Suitable solvents for plasticizing the thermoplastic resin include tetrahydrofuran (THF) and methyl ethyl ketone (MEK) for vinyl chloride resins, and THF, MEK, and MEK for urethane resins.
Dimethylacetamide, dimethylsulfoxide and the like are suitable. The thermoplastic resin solution solvent 32 is a solution obtained by dissolving the above-mentioned thermoplastic resin with a solvent. For example, polyurethane is used as the thermoplastic resin, and TH is used as the solvent.
When F is used, it is preferable to use a solution containing 5 to 20% by weight of polyurethane. This solvent solution 32
Has a viscosity of 100 to 10000 cp, preferably 100
It is adjusted in advance to 0 to 5000 cp. In the present invention, the balloon film constituting the balloon portion 4 may be formed by blow molding the parison (blow molding method).

As shown in FIG. 4, a tapered tapered portion 4c and a distal end sealing portion 7 which are tapered are integrally formed at the distal end of the balloon portion 4 thus formed.
At the proximal end of the balloon portion 4, a tapered tapered portion 4b and a proximal end sealing portion 5 that are tapered are integrally formed.

Next, the joining portion 5a of the proximal end sealing portion 5 of the balloon portion 4 is joined to the outer periphery of the distal end of the first outer tube member 6a. At the time of the joining, as shown in FIG. 6, the mandrel 40 is inserted into the distal end of the first outer tube member 6a, and then the outer end of the distal end of the member 6a is attached to the proximal end of the balloon portion 4. The joining portion 5a of the sealing portion 5 is overlapped. Then, the outer periphery of the joint portion 5a is covered with a heat-resistant film 42, and the heat-resistant film 42 is heated by a mold 44, so that the joint portion 5a is thermally fused to the distal end of the first outer tube member 6a. Let it. The heating temperature is not particularly limited, but preferably 100 to 300 °
C, particularly preferably 150 to 250 ° C.

As the heat-resistant film, for example, a fluororesin tube is used, and its axial length is preferably longer than the joining portion 5a, for example, about 20 mm. A cut having a length of about 3 mm may be formed at one end in the axial direction of the tube. This is because the heat-resistant film can be easily removed after the heat-sealing.

Thereafter, a through hole 21 is formed in the tube wall at a predetermined position in the axial direction of the first outer tube member 6a so that the inner tube 12 can pass therethrough, as shown in FIG.
Next, the inner tube 12 to which the contrast ring 15 is attached is prepared, and integrated into the lumen of the inner tube 12 through a wire-like mandrel. The inner tube 12 with the integrated mandrel is passed through the through hole 21 into the inner lumen of the first outer tube member 6a, and the distal end of the inner tube 12 is projected from the distal end sealing portion 7 of the balloon portion 4, The contrast ring 15 is positioned at the center of the balloon section 4. Before and after that, the heat sealing tube is positioned on the outer periphery of the first outer tube member 6a. The heat seal tube is
This is similar to the heat-shrinkable film 42 shown in FIG.

Thereafter, a heat sealing mandrel is inserted into the inside from the proximal end of the first outer tube member 6a, and the tip end of the mandrel is positioned near the through hole 21. The outer tube 6a is prevented from being crushed.
The base end of the mandrel has an outer diameter substantially equal to or less than the inner diameter of the first outer tube member 6 a, and an axial recess is formed at the distal end thereof to receive the outer circumference of the inner tube 12. It is. Next, the heat-sealing tube is
The tube is moved axially around the outer periphery of the outer tube member 6a so that the heat-sealing tube has the outer periphery of the first outer tube 6a near the through-hole 21 and the inner tube 1 that protrudes from the through-hole 21.
2 and the outside. Then, using a heat-sealing mold, heating is performed by pressing from the outside of the heat-sealing tube, so that the edge of the through-hole 21 and the inner tube 12 are heated.
The outer tube wall is heat-sealed. The heating temperature is not particularly limited, but is preferably 100 to 300 ° C, particularly preferably 150 to 250 ° C.

After that, the mandrel is taken out and the heat sealing tube is removed. Thereafter, the outer tube wall of the inner tube 12 and the through-hole 21 which are heat-sealed in the heat-sealing process are formed.
The unnecessary portion of the inner tube 12 located outside from the heat-sealed portion is removed by cutting with a cutter or the like, leaving a heat-sealed portion with the inner edge of the inner tube. As a result, the proximal end opening 22 of the inner tube 12 is formed to open outside the tube wall of the first outer tube member 6a. The proximal end opening 22 has a substantially elliptical shape in this example. In addition, before or after these steps, or simultaneously, the distal end of the inner tube 12 is heat-fused to the distal end sealing portion 7 of the balloon portion 4 by a similar heat sealing method, and the predetermined length is obtained. Is cut off.

Thereafter, the distal end of the second outer tube portion 6b is joined to the proximal end of the first outer tube member 6a. At the time of the joining, first, a heat sealing tube is put on the outer periphery of the second outer tube member 6b,
a into the lumen at the proximal end of the second outer tube member 6b.
Press the distal end of the Then, the second outer tube member 6
A mandrel is inserted along the axial direction into the inside of the third lumen 24 of b, and its tip is projected to the inside of the first outer tube member 6a. Before or after or at the same time, a reinforcing rod 28 is inserted along the axial direction into the fourth lumen 26 of the second outer tube member 6b, and the distal end thereof is formed on the outer periphery of the first outer tube member 6a. It is positioned below the end opening 22.

Thereafter, the heat-sealing tube is moved in the axial direction, and the joint 9 between the first outer tube member 6a and the second outer tube member 6b is moved by the heat-sealing tube.
And heat-sealing is performed using a mold under the same heat sealing conditions as those described above.

Thereafter, while removing the heat sealing tube and the mandrel, the connector 8 shown in FIG. 1 is joined to the proximal end of the second outer tube member 6b by means such as heat fusion. Thereafter, if necessary, the outer peripheral surface of the outer tube 6 is coated with a coating material made of a hydrophilic polymer substance having lubricity in a wet state, and the balloon catheter 2 shown in FIG. 1 is obtained.

Next, a method of performing PTCA treatment using the balloon catheter 2 of the embodiment shown in FIG. 1 will be described. First, air in the balloon catheter 2 is removed as much as possible. Therefore, a suction / injection means such as a syringe is attached to the port of the connector 8, a liquid such as a blood contrast agent (for example, containing iodine) is put into the syringe, and suction and injection are repeated, and the third lumen 24, the first lumen The air in 10 and the balloon section 4 is replaced with a liquid.

In order to insert the balloon catheter 2 into an arterial blood vessel, first, a guide wire for a guide catheter (not shown) is inserted into the blood vessel by Seldinger method or the like so that the distal end thereof reaches, for example, near the heart. I do. Thereafter, the guide catheter is inserted into the arterial blood vessel along the guide wire for the guide catheter, and the distal end thereof is positioned at the entrance of the coronary artery of the heart having the stenosis. The stenosis is formed by, for example, thrombus or arteriosclerosis.

Next, only the guide wire for the guide catheter is pulled out, a guide wire for a balloon catheter thinner than the guide wire is inserted along the guide catheter, and the distal end thereof is inserted to a position where it passes through the stenosis.

Thereafter, the distal end of the guidewire is inserted into the distal open end 20 of the balloon catheter 2 shown in FIG. 1, passed through the first lumen 14, and withdrawn from the proximal end opening 22. Then, the balloon catheter 2 is passed through the guide catheter along the guide wire 42 in a state where the balloon portion 4 is folded. Then, the balloon portion 4 of the balloon catheter 2 is inserted to a position just before the stenosis.

Thereafter, the folded balloon portion 4 of the balloon catheter 2 is inserted between the stenotic portions along a guide wire. Next, while observing the position of the balloon portion 4 with an X-ray fluoroscope, the balloon portion 4 is accurately positioned at the center of the stenosis. By inflating the balloon portion 4 at that position, the stenotic portion of the blood vessel can be widened and good treatment can be performed. The balloon section 4 is inflated by injecting a liquid into the balloon section 4 from the port of the connector 8 shown in FIG. 1 through the third lumen 24 and the first lumen 10.

The expansion time is not particularly limited, but is, for example, about 1 minute. Thereafter, the liquid is quickly drained from the balloon portion 4 to deflate the balloon portion, thereby securing blood flow on the peripheral side of the dilated stenosis. The expansion of the stenosis must be performed stepwise so as not to damage the blood vessel. First, a balloon catheter 2 having a balloon portion 4 having a small outer diameter is inserted along a guide wire, and a balloon having a larger outer diameter is sequentially inserted. The balloon catheter 2 having the part 4 is exchanged. At that time, since the balloon catheter 2 according to the present embodiment is a monorail type balloon catheter, the proximal end of the guide wire 42 is slightly longer than a portion corresponding to the length of the inner tube 12. The balloon catheter can be exchanged simply by extending it outward.

In the balloon catheter 2 according to the present embodiment, only the distal end of the balloon catheter 2 adopts a so-called coaxial catheter tube structure composed of an outer tube 6 and an inner tube 12. The lumen 14 is used as a guide wire insertion lumen. For this reason, a conventional balloon catheter having a so-called double-lumen catheter tube (Japanese Unexamined Patent Publication No.
The balloon catheter 2 according to the present embodiment is described in comparison with Japanese Patent Application Laid-Open Nos. 3-288167 and 2-307479.
Then, the outer diameter of the first outer tube member 6a can be easily reduced. Further, in the balloon catheter 2 according to the present embodiment, the proximal end opening 22 of the inner tube 12 serving as the proximal end side outlet of the guide wire penetrates the tube wall located in the longitudinal direction of the outer tube 6. In the opening 22, the inner tube 12 and the outer tube 6 have a double structure, and are hardly kinked.

Further, in the balloon catheter 2 according to the present embodiment, the proximal end opening 22 of the inner tube 12 serving as the proximal end side outlet of the guide wire 42 is connected to the outer tube 6.
Only penetrates the tube wall located in the middle of the longitudinal direction of the catheter tube 2 and is opened to the outside. There is no need to make a step over the entire length of the catheter tube 2, and the balloon catheter 2 has excellent insertion characteristics. In addition, since it has a structure that does not easily kink, the balloon catheter 2 has excellent pushing characteristics.

In this embodiment, as shown in FIG. 2, the reinforcing rod 28 is disposed inside the first outer tube member 6a from the vicinity of the opening 22 to the proximal end side. The pushing characteristics are further improved, and the distal end side of the catheter tube becomes flexible, so that the insertion characteristics in a body cavity such as a meandering blood vessel are further improved.

Further, in the present embodiment, since the distal end portion 28a of the reinforcing rod 28 is not fixed to the inner wall of the first outer tube member 6a, the balloon catheter 2 has a large number of bifurcated portions like a coronary artery. Even when inserted into a thin blood vessel, the distal end of the first outer tube member 6a is flexibly deformed corresponding to the bent portion of the blood vessel. This is because the distal end 28a of the reinforcing rod 28 is not fixed to the inner wall of the first outer tube member 6a.
It is considered that the distal end of “a” can be freely deformed without being restricted by the reinforcing rod 28.

In particular, in the present embodiment, the proximal end sealing portion 5 of the balloon portion 4 has a joint portion 5a that is overlapped and joined to the distal end portion of the outer tube portion 6, and a non-joined portion that does not overlap. 5b. The non-joined portion 5a of the proximal end sealing portion 5 of the balloon portion 4 is a portion that hardly contributes to a therapeutic effect by expansion of the balloon portion 4, but by providing such a portion, the distal end portion of the balloon catheter 2 is provided. Flexibility is improved. This is because the non-joined portion 5b is a part of the balloon portion 4 and is more flexible than the outer tube portion 6.

Therefore, even when the balloon catheter 2 of the present embodiment is inserted into a thin blood vessel having many branches such as a coronary artery, the distal end of the balloon catheter 2 is flexible in correspondence with the bent part of the blood vessel. Deform to. That is, in the balloon catheter 2 of the present embodiment, the insertion characteristics and the pushing characteristics of the balloon catheter 2 are improved.

In the method for manufacturing a balloon catheter according to the present embodiment, the balloon catheter 2 can be manufactured relatively easily, and the bonding between the balloon portion 4 and the outer tube 6 is strong. Become.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention. For example, in the above-described embodiment, the outer tube 6 is configured by the first outer tube member 6a and the second outer tube member 6b, but in the present invention, the outer tube 6 is configured by a single tube that is continuous in the axial direction. It is also possible.

The use of the balloon catheter according to the present invention is not limited to the above-mentioned use.

[0069]

As described above, according to the present invention, there is provided a balloon catheter which is flexibly deformed in accordance with a bent portion of a blood vessel and has particularly excellent insertion characteristics and push-in characteristics, and a method of manufacturing the same. Can be.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a balloon catheter according to one embodiment of the present invention.

2A is a sectional view taken along the line IIB-IIB shown in FIG. 1, FIG. 2B is a sectional view taken along the line IIB-IIB shown in FIG. 1,
FIG. 2C is a sectional view taken along the line IIC-IIC shown in FIG.
FIG. 2D is a sectional view taken along line IID-IID shown in FIG. 1.

FIG. 3 is a side view of the reinforcing rod shown in FIG.

FIG. 4 is a longitudinal sectional view of a main part of the balloon catheter shown in FIG.

FIG. 5 is a schematic view showing a manufacturing process of a balloon portion in the balloon catheter according to the present embodiment.

FIG. 6 is a cross-sectional view of a lumbar region showing a joining process between a proximal end sealing portion of a balloon portion and a distal end portion of a catheter tube.

[Explanation of symbols]

 2 ... Balloon catheter 4 ... Balloon part 4a ... Cylindrical part 4b, 4c ... Tapered reduced diameter part 5 ... Proximal end sealing part 5a ... Joining part 5b ... Non-joining part 7 ... Distal end sealing part 6 ... Outside Tube 6a ... First outer tube member 6b ... Second outer tube member 8 ... Connector 10 ... First lumen 12 ... Inner tube 14 ... Second lumen 20 ... Distal end opening 21 ... Through hole 22 ... Proximal end opening 24 ... Third lumen 26 ... Fourth lumen 28 ... Reinforcing rod

Claims (4)

[Claims] 1. A catheter tube having at least one balloon inflation lumen formed along a longitudinal direction; a tubular portion having an outer diameter larger than an outer diameter of the catheter tube in an inflated state; A distal end sealing portion integrally formed at a distal end of the tubular portion and having an outer diameter smaller than the tubular portion; and a distally sealed portion integrally formed at a proximal end of the tubular portion. A balloon portion having a proximal end sealing portion having an outer diameter smaller than a cylindrical portion, wherein the proximal end sealing portion overlaps a distal end of the catheter tube. And a non-joined portion having substantially the same outer diameter as the joined portion and not overlapping the distal end of the catheter tube. 2. In the proximal end sealing portion of the balloon portion, a ratio of an axial length of the joined portion to an axial length of the non-joined portion is in a range of 1: 1 to 1:10. The balloon catheter according to claim 1, wherein: 3. The balloon catheter according to claim 1, wherein a joint portion at a proximal end sealing portion of the balloon portion is heat-fused to a distal end portion of the catheter tube. 4. Inserting a mandrel into the distal end of the catheter tube, overlapping the outer peripheral portion of the distal end of the catheter tube with a joint at the proximal end sealing portion of the balloon portion, Covering the outer periphery of the joint portion with a heat-resistant film, and heating the heat-resistant film to thermally fuse the joint portion to the distal end of the catheter tube.