JPH0838618A - Balloon catheter for expanding celom and its production - Google Patents

Abstract

PURPOSE:To provide a balloon catheter for expanding the celom capable of easily and exactly progressing the balloon membrane of the balloon catheter down into the constricted part position of the celom and effectively exhibiting the celom expanding function of the balloon catheter even if the constricted part formed in the celom, such as blood vessel, is narrow, is hard, is eccentric or meanders. CONSTITUTION:The outside diameter at the front end 7 of the cylindrical balloon membrane 4 and the outside diameter in the central part 22 thereof, which are respectively defined as RS and R1, and the film thicknesses at the front end 7 and central part 22 of the cylindrical balloon membrane 4, which are respectively defined as tS and t1, are so set that the relation therebetween satisfies an equation R1Xt1-t1<2>>=0.9X(RSXtS-tS<2>). Production of the balloon membrane 4 satisfying such relation is executed by first preparing a tubular parison which is larger in the film thickness in the central part than the film thickness at both ends. This parison is then subjected to blow molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balloon catheter which is expanded by inserting it into a body cavity such as a blood vessel to expand a channel in the body cavity, and more specifically, for treating a stenosis in the blood vessel. In order to expand this stenosis,
The present invention relates to a balloon catheter for expanding a body cavity, which is used for improving blood flow on the peripheral side of a stenosis.

[0002]

2. Description of the Related Art In order to treat a stenosis in a blood vessel, the balloon catheter is inserted into the blood vessel and the balloon membrane is inflated to expand the stenosis to improve the blood flow on the peripheral side of the stenosis. As an over-the-wire type in which a guide wire is inserted from the proximal end of the catheter,
A monorail type balloon catheter in which a guide wire is exposed from the middle of the catheter is often used. In these types of balloon catheters, the guide wire is first passed through the intravascular stenosis, and then the balloon catheter is fed to the stenosis along this guide wire to expand the stenosis by inflating the balloon membrane. .

These types of balloon catheters are
An inner tube having a lumen through which a guide wire can be inserted, a catheter tube coaxially attached to the inner tube, a distal end portion and a proximal end portion, and the proximal end portion is a catheter tube. A foldable balloon membrane attached to the tip of the inner tube and the tip attached to the outer circumference of the tip of the inner tube.

These types of balloon catheters are
In terms of operability, it has an excellent effect. With these types of balloon catheters, in order to expand the stenosis in the blood vessel and improve blood flow on the distal side of the stenosis, the catheter is advanced along a guide wire previously inserted into the stenotic blood vessel, Accurate placement of the balloon membrane in the stenosis of the blood vessel is important. Since the tip of the balloon catheter is pressed into the extremely narrow stenosis,
It is preferable that the distal end portion of the balloon catheter has a small outer diameter so that it can easily enter the stenotic portion.

[0005]

However, in the conventional balloon catheter, the balloon membrane is formed by blow molding (see, for example, JP-A-5-192408).
Japanese Patent Publication No. 28341/1990), and has the following problems. That is, in blow molding, while heating a tubular parison having a uniform film thickness in the axial direction, a pressure fluid is introduced into the interior of the tubular parison to inflate the parison, thereby forming a tubular balloon membrane 10 as shown in FIG.
0 is molded. The balloon membrane 100 has a large outer diameter R ₁ at the balloon membrane central portion 102 and a small outer diameter R _s at the distal end portion 104 and the proximal end portion 106 thereof. Tapered portions 108 and 110 are formed between the distal end portion 104 and the proximal end portion 106 and the balloon membrane central portion 102.

If such a balloon membrane 100 is formed by blow molding from a tubular parison having a uniform wall thickness in the axial direction, the film thickness t _l at the central portion 102 of the balloon membrane, particularly at the tip portion 104, is obtained. The film thickness t _s of the film becomes thicker. This is because the balloon membrane central portion 102 and the tip portion 104 have different elongation rates due to blow molding.

When the thickness of the tip portion 104 is large, the outer diameter of the tip portion of the balloon catheter is increased and the rigidity of the tip portion is increased. As a result, it is difficult to satisfactorily push the balloon catheter to a narrow stenosis, a hard stenosis, an eccentric stenosis or a meandering stenosis.

If the balloon membrane of the balloon catheter cannot be pushed accurately into the stenosis, the original function of the balloon catheter, which is to expand the stenosis to improve blood flow, cannot be achieved. In order to reduce the film thickness at the tip of the balloon film, it is conceivable to reduce the thickness of the tubular parison before blow molding. However, in that case, the film thickness at the central portion of the balloon film becomes too thin after blow molding, and the pressure resistance may become insufficient. Since the balloon membrane is designed to expand in a body cavity such as a blood vessel of a patient, it should not have an insufficient pressure resistance. Also,
Since the balloon membrane is folded and inserted into a body cavity such as a blood vessel of a patient, it is preferably as thin as possible so that it can be easily inserted into the blood vessel.

Therefore, it is necessary to design the thickness of the central portion of the balloon film to be as thin as possible so that the pressure resistance is sufficient. Therefore, the wall thickness of the tubular parison is determined according to the designed film thickness of the central portion of the balloon film, and the film thickness of the tip portion 104 of the balloon film 100 is unavoidably increased.

In Japanese Patent Laid-Open No. 4-176473, for the purpose of reducing the film thickness of the tapered portions 108 and 110 of the balloon film 100, the balloon film is stretched in the axial direction after blow molding, and the tapered portion 108 is formed. , 110 is disclosed. However, after the blow molding, it is very difficult to perform the stretching process so as to change the film thickness of the tapered portions 108 and 110. Even if the film thickness of the tapered portions 108 and 110 can be changed, as long as the film thickness of the tip portion 104 is not thin,
When inserted into a blood vessel, the rigidity of the tip cannot be sufficiently reduced.

The present invention has been made in view of such circumstances, and the catheter tip is flexible even when the narrowed portion formed in the body cavity such as a blood vessel is narrow, hard, eccentric, or meandering. It is sufficiently thin and can advance the balloon membrane of the balloon catheter to the position of the narrowed part of the body cavity easily and accurately, and can effectively demonstrate the function of expanding the body cavity of the balloon catheter. An object of the present invention is to provide a balloon catheter and a manufacturing method thereof.

[0012]

In order to achieve the above object, the first balloon catheter for body cavity expansion according to the present invention is inserted into a body cavity such as a blood vessel and inflated to form a channel in the body cavity. A balloon catheter for expanding a body cavity having a tubular balloon membrane to be inflated, wherein the outer diameter of the distal end portion and the outer diameter of the central portion of the tubular balloon membrane are R _s and R _l , respectively. When the thicknesses of the distal end portion and the central portion of the balloon film are t _s and t _l , respectively, the relationship between these R _s , R _l , t _s, and t _l satisfies the following expression (1).

[0013]

R _l × t _l −t _l ² ≧ 0.9 × (R _s × t _s −t _s ² ) (1) The method for manufacturing the first balloon catheter for body cavity expansion according to the present invention is , A step of preparing a tubular parison having a thick film thickness at the central portion with respect to the film thickness at both end portions, and blow molding this parison, and a tubular balloon membrane central portion having a large outer diameter, And a step of forming a balloon membrane having a tubular distal end portion and a proximal end portion having small outer diameters located at both ends.

As a method for preparing a tubular parison having a film thickness in the central portion which is thicker than that in both end portions, both ends of the parison having a uniform wall thickness in the axial direction are formed before the blow molding of the parison. There is a method of thinning the part. Examples of the thin-wall processing means include means for heating both ends of the parison and passing through the forming die, and means for cutting both ends of the parison by machining. The cutting process is
It is preferable because the work is easy and the both ends of the parison can be surely thinned.

Further, as another method for preparing a tubular parison having a larger film thickness in the central portion than in the film thickness at both end portions, the central portion of the first parison having a uniform wall thickness in the axial direction. There is a method of mounting a second parison having a shorter axial length and a larger outer diameter than the first parison on the outer circumference.

As another method for producing the first balloon catheter for body cavity dilation according to the present invention, at least the tip portion of the balloon membrane is formed after blow molding a parison having a uniform wall thickness in the axial direction. There is a method of reducing the film thickness of the tip portion of the balloon film by cutting.

The second balloon catheter for expanding a body cavity of the present invention has a balloon membrane for expanding a flow channel in the body cavity by being inserted into a body cavity such as a blood vessel and expanding, and a distal end at the proximal end of the balloon membrane. A catheter tube that is connected and has a first lumen for inflating the balloon membrane by introducing a fluid into the inside of the balloon membrane, and an open end at the tip portion, and the balloon membrane at the outer periphery of the tip portion. Is a balloon catheter for dilating a body cavity, which has an inner tube having a second lumen formed therein, the distal end of which is connected to the balloon section, and which extends in the axial direction inside the catheter section. The outer diameter of the tip of the inner tube to be connected is smaller than the outer diameter of the inner tube located at the center of the balloon membrane.

As means for reducing only the outer diameter of the tip of the inner tube to a small diameter, it is possible to adopt means for passing the tip of the inner tube through a forming die while heating, or means for cutting by machining. it can. The tip portion of the balloon membrane is connected to the tip portion of the reduced diameter inner tube by means such as adhesion or heat fusion.

The balloon catheter for expanding the body cavity is preferably used for percutaneous coronary angioplasty (PTCA).

[0020]

In the first balloon catheter for expanding a body cavity according to the present invention, the thickness of the distal end portion of the balloon membrane is designed to be thin so as to satisfy the above expression (1). In the conventional example,
The film thickness at the tip of the balloon film was formed thicker than necessary in order to secure the film thickness at the center of the balloon film after blow molding. In the present invention, by adopting the above-described manufacturing method of the present invention, it becomes possible to form a thin film at the tip portion of the balloon film without lowering the pressure resistance of the balloon film at the central portion of the balloon film.

If the thickness of the tip of the balloon membrane becomes thinner,
The outer diameter of the distal end of the balloon catheter also becomes smaller, and even in the case of narrow stenosis, strong stenosis, or hard stenosis, the balloon catheter can be easily pushed along the guide wire, and the balloon membrane can be accurately placed in the stenosis. Can be located.

In the second balloon catheter for expanding body cavity according to the present invention, only the outer diameter of the tip portion of the inner tube is reduced to a small diameter, and the tip portion of the balloon membrane is adhered or heat-sealed to that portion. Therefore, the outer diameter of the distal end portion of the balloon catheter is further reduced. Further, the tip portion of the inner tube becomes thin, and the flexibility of that portion is improved. As a result, in the balloon catheter of the present invention, even if the stenotic portion is eccentric to the blood vessel or the meandering stenotic portion, the distal end of the balloon catheter is flexibly bent, so that the balloon catheter can be pushed well along the guide wire. You can

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The balloon catheter for expanding a body cavity according to the present invention will be described below in detail with reference to the embodiments shown in the drawings. First Embodiment A balloon catheter 2 according to the present embodiment shown in FIG. 1 is used, for example, for percutaneous coronary angioplasty (PTCA), dilatation of blood vessels of extremities, upper ureteral dilatation, renal vasodilation, etc. It is used in a method and is used to dilate a stenosis formed in a blood vessel or other body cavity. In the following description, the case where the balloon catheter 2 of this embodiment is used for PTCA will be described as an example.

Dilatation balloon catheter 2 of this embodiment
Is a balloon membrane 4, a catheter tube 6, a branch portion 8,
And an inner tube 10. The proximal end 5 of the balloon membrane 4 is connected to the distal end of the catheter tube 6, and the catheter tube 6
A branch portion 8 is connected to the base end portion of the.

The distal end portion 7 of the balloon membrane 4 has an inner tube 10
It is connected to the outer circumference of the tip of the. Balloon membrane 4 and inner tube 10
And the balloon membrane 4 and the catheter tube 6 are connected by a joining means such as heat fusion or adhesion. A second lumen 12 for inserting a guide wire or the like is formed inside the inner tube 10. The inner tube 10 extends axially in the balloon membrane 4, the catheter tube 6, and the branch portion 8 in a substantially coaxial state. Inside the catheter tube 6,
A first lumen 14 is provided between the catheter tube 6 and the inner tube 10.
Is formed. An expansion port 16 formed in the branch portion 8 communicates with the first lumen 14, and a pressure fluid is introduced from the expansion port 16 to inflate the folded balloon membrane 4.

First lumen 14 through expansion port 16
The pressure fluid introduced into the inside is not particularly limited, but may be, for example, 50/50 of a radiopaque dye and a salt.
A mixed aqueous solution or the like is used. The reason why the radiopaque dye is included is to use radiation to image the positions of the balloon membrane 4 and the catheter tube 6 when the balloon catheter 2 is used. The pressure of the pressure fluid for inflating the balloon membrane 4 is not particularly limited, but is 3 to 12 in absolute pressure.
Atmospheric pressure, preferably about 4-8 atm.

A guide port 18 is formed in the branch portion 8 separately from the expansion port 16 along the axis of the inner tube 10. The inner pipe 10 is formed so that the guide port 18 communicates with the second lumen 12 formed in the inner pipe 10.
The open end of the base end side is connected to the branch part 8. The connection between the catheter tube 6 and the branch portion 8 and the connection between the inner tube 10 and the branch portion 8 are performed by means such as heat fusion or adhesion.

The catheter tube 6 is preferably made of a material having a certain degree of flexibility, such as polyethylene, polyethylene terephthalate, polypropylene, ethylene-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 and the like can be used, and preferably polyethylene, polyamide or polyimide is used. The outer diameter of the catheter tube 6 may be uniform in the axial direction, but a stepped portion or a tapered portion may be formed in the middle so that it is small in the vicinity of the balloon membrane 4 side and large in other portions. This is because by increasing the cross section of the flow path of the first lumen 14, the time for deflating the balloon membrane 4 is shortened. This is because the balloon membrane 4 needs to be inflated for about 1 minute and then immediately deflated, in order to secure the blood flow to the peripheral side.

The outer diameter of the catheter tube 6 is preferably about 0.6 to 1.0 mm near the connection with the balloon membrane 4.
On the side of the branch portion 8, it is preferable that the distance is about 0.8 to 1.2 mm. The wall thickness of the catheter tube 6 is preferably about 0.05 to 0.15 mm. The inner tube 10 may be made of, for example, the same material as the catheter tube 6, and is preferably made of polyethylene, polyamide, or polyimide. As a reinforcing material,
Stainless wire, nickel-titanium alloy wire, etc. may be used. The inner diameter of the inner tube 10 is not particularly limited as long as it can be inserted through the guide wire, and is, for example, 0.1
It is 5 to 1.00 mm, preferably 0.25 to 0.60 mm. The wall thickness of the inner tube 10 is preferably 0.05 to 0.15 mm. The total length of the inner tube 10 is determined according to the axial length of the balloon catheter 2 inserted into the blood vessel and is not particularly limited, but is, for example, about 120 to 150 mm, preferably about 130 to 140 mm. An open end 20 is formed at the tip of the inner tube 10. The guide wire inserted through the second lumen 12 of the inner tube 10 can be led out from the open end 20.

A radiopaque marker may be attached to one or more locations around the inner tube 10 located in the balloon membrane 4. As the marker, for example, a metal tube made of gold, platinum, tungsten, iridium, or an alloy thereof, a metal spring, or the like can be used. By attaching this marker around the inner tube 10 in the balloon membrane, the position of the balloon membrane 4 and the length of the expanded portion of the balloon can be detected under fluoroscopy during use of the balloon catheter 2.

The branch portion 8 is made of polycarbonate, for example.
It is preferably molded with a thermoplastic resin such as polyamide, polysulfone, polyacrylate, methacrylate-butylene-styrene copolymer. In this embodiment, the balloon membrane 4
Is an outer diameter R that is uniform in the axial direction, as shown in FIGS.
A tubular balloon membrane central portion 22 having _l (when the balloon membrane is inflated) and the balloon membrane central portion 2 provided at both ends thereof.
It has a cylindrical front end portion 7 and a base end portion 5 each having outer diameters R _s and R _s ′ smaller than 2. The distal end portion 7 and the proximal end portion 5 and the balloon membrane central portion 22 are continuously formed by tapered portions 24 and 26 whose outer diameters are gradually reduced in the axial direction.

The thickness t _l of the balloon membrane 4 at the central portion 22 of the balloon membrane is not particularly limited, but is 15 to 200 μm,
It is preferably about several tens of μm. The balloon membrane 4 is
The shape is not particularly limited as long as it is cylindrical, and may be cylindrical or polygonal. The outer diameter R ₁ of the balloon membrane 4 at the central portion 22 of the balloon membrane when inflated is determined by factors such as the inner diameter of the blood vessel, and is preferably about 1.5 to 4.0 mm. The axial length L of the balloon membrane central portion 22 of the balloon membrane 4 is
It 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 4
It is 0 mm. The balloon membrane 4 before being inflated is folded and wrapped around the inner tube 10 shown in FIG. 1, and has a diameter equal to or less than the outer diameter of the catheter tube 6.

The material forming the balloon membrane 4 is preferably a material having a certain degree of flexibility, for example, polyethylene, polyethylene terephthalate, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, poly. Vinyl chloride (PVC), a cross-linking type ethylene-vinyl acetate copolymer, polyurethane, polyamide, polyamide elastomer, polyimide, polyimide elastomer, silicone rubber, natural rubber and the like can be used, and polyethylene, polyethylene terephthalate and polyamide are preferable.

In this embodiment, as shown in FIG. 2, the outer diameter of the tip portion 7 of the balloon membrane 4 and the outer diameter of the central portion 22 are R _s and R ₁ , respectively, and the tip portion 7 of the balloon membrane 4 and When the thickness of the central portion 22 is t _s and t _l , respectively, the relationship between these R _s , R _l , t _s, and t _l is set so as to satisfy the following equation (1). A method for manufacturing a balloon film so as to satisfy the following formula (1) will be described later.

[0035]

[Formula 3] R _l × t _l −t _l ≧ 0.9 × (R _s × t _s −t _s ² ) ... (1) In a conventional balloon membrane of a balloon catheter, a balloon is formed by ordinary blow molding. Since the film is manufactured, it has the relationship of the following formula (2) as shown in FIG. 3 described later.

[0036]

Equation 4] ^{_{R l × t l -t l 2}} = R s × t s -t s 2 ...... (2) the meaning of equation (2), for example, in FIG. 2, the central portion 22 of the balloon membrane 4 Area of the membrane cross section (left side of Equation 2)
Is the area of the membrane cross section at the tip 7 of the balloon membrane 4 (equation 2
Right side of). Since the conventional balloon membrane is formed by blow molding a parison having a uniform wall thickness in the axial direction, the above formula (2) is established.

In this embodiment, since the balloon membrane 4 is manufactured by adopting the manufacturing method described later, the film thickness of the tip portion 7 of the balloon membrane 4 is satisfied so as to satisfy the above expression (1). It was able to reduce the t _s. In this example,
The wall thickness t _s ′ of the base end portion 5 of the balloon film 4 can also be formed thin so as to satisfy the following expression (3).

[0038]

R _l × t _l −t _l ² ≧ 0.9 × (R _s ′ × t _s ′ −t _s ′ ² ) (3) Next, a method for manufacturing the balloon membrane 4 shown in FIG. Will be described. First, as shown in FIG. 3A, a tubular parison 4a having a uniform thickness and an outer diameter R ₀ in the axial direction is prepared. The outer diameter R ₀ of the parison 4a is not particularly limited, but is 0.2 to 2.0 mm, preferably 0.5 to 1.5 mm. The thickness of the parison 4a is not particularly limited, but is 0.2 to 0.9 mm, preferably 0.3 to 0.7 mm. The length L ₀ of the parison 4a is not particularly limited, but is 10 to 500 mm, preferably 20 to 300 mm.

Next, as shown in FIG. 3B, both ends 5a and 7a of the parison 4a are thinned. As a method of thin-walling, both ends 5a, 7a of the parison 4a are heated and passed through a molding die, and both ends 5a of the parison 4a,
A method of cutting 7a by machining can be exemplified. In the method of passing through the molding die, the inner diameter of the parison 4a does not change by using the mandrel.
The cutting process is preferable because the work is easy and both ends of the parison can be surely thinned.

The outer diameters of both end portions 5a and 7a after thinning are
It is 0.2 to 1.6 mm, preferably 0.4 to 1.2 mm. The wall thickness is 5 compared to the wall thickness in the central part of the parison.
0 to 400%, preferably 100 to 300%, specifically 0.05 to 0.40 mm, preferably 0.1 to
It is 0.3 mm. Further, both end portions 5a, 7 to be thinned
The length range L _{1 of a} is ₁ to 100 mm, preferably 2 to 5
It is 0 mm.

After that, the parison whose both ends are thin-walled is mounted in a blow molding die, and while heating,
A pressure gas or a pressure liquid is flown inside the parison 4a and blow molding is performed to form a balloon film 4 having a shape as shown in FIG. Next, a method of performing PTCA treatment using the balloon catheter 2 of the embodiment shown in FIG. 1 will be described.

First, the air in the balloon catheter 2 is removed as much as possible. Therefore, the guide port 1 of the branch section 8
A liquid such as physiological saline is put into the second lumen 12 in the inner tube 10 from 8 to replace the air in the second lumen 12.
In addition, a suction / injection means such as a syringe is attached to the expansion port of the branch portion 8, a liquid such as a blood contrast agent (containing iodine, for example) is put into the syringe, suction and injection are repeated, and the first lumen 14 and the balloon. The air in the membrane 4 is replaced by the liquid.

To insert the balloon catheter 2 into an arterial blood vessel, first, a guide catheter guide wire (not shown) is inserted into the blood vessel by the Seldinger method or the like so that its tip reaches, for example, the vicinity of the heart. To do. Then, along the guide wire for the guide catheter, as shown in FIG.
The guide catheter 32 shown in (1) is inserted into the arterial blood vessel 34, and its tip is positioned at the coronary artery entrance 40 of the heart 38 having the stenosis 36. The narrowed portion 36 is formed by, for example, thrombus or arteriosclerosis.

Next, only the guide wire for the guide catheter is pulled out, the guide wire 42 for the balloon catheter, which is thinner than the guide wire, is inserted along the guide catheter 32, and the tip thereof is inserted to a position where it passes through the narrowed portion 36. After that, the proximal end of the guide wire 42 shown in FIG. 4 is inserted into the open end 20 of the balloon catheter 2 shown in FIG. 1 and passed through the second lumen 12 of the inner tube 10, and with the balloon membrane 4 folded, The balloon catheter 2 is passed through the guide catheter 32 shown in FIG. Then, as shown in FIG. 4, the balloon membrane 4 of the balloon catheter 2 is inserted up to the front of the stenotic portion 36. Alternatively, after removing the guide wire for the guide catheter from the guide catheter 32, the guide port 18 at the bifurcation section is used to remove the second inner tube.
A balloon catheter having a guide wire inserted into the lumen 12 is inserted from the base of the guide catheter shown in FIG. 4 to guide the balloon membrane 4 into the coronary artery,
The tip of 2 may be inserted to a position where it passes through the narrowed portion 36.

Thereafter, as shown in FIG. 5 (A), the distal end portion 7 of the balloon membrane formed at the tip of the balloon catheter 2 is inserted along the guide wire 42 between the narrowed portions 36. At this time, in this embodiment, since the thickness of the distal end portion 7 of the balloon membrane 4 is thin, the outer diameter is small, and when the gap between the guide wire 42 and the narrowed portion 36 is small, a strong narrowed portion or a hard narrowed portion is formed. 5B and 5C even in a constricted part, etc.
As shown in, the balloon catheter 2 can be easily pushed forward. The reaction force generated when the balloon catheter 2 is pushed into the narrowed portion 36 is received by the tip side bent portion 44 of the guide catheter 32 shown in FIG. 4 coming into contact with the inner wall of the blood vessel 34, so that this reaction force is small. Is preferred. In this embodiment, this reaction force becomes small.

Next, as shown in FIG. 5C, while observing the position of the balloon film 4 with an X-ray fluoroscope or the like, the balloon film 4 is accurately positioned at the center of the stenosis 36. By inflating the balloon membrane 4 at that position, the narrowed portion 36 of the blood vessel 34 can be widened and good treatment can be performed. The balloon membrane 4 is inflated by injecting a liquid such as a contrast agent into the balloon membrane 4 through the first lumen 14 from the expansion port 16 shown in FIG.

The expansion time is not particularly limited, but is, for example, about 1 minute. After that, the liquid is quickly drained from the balloon film 4 to contract the balloon film, and the blood flow on the peripheral side of the expanded stenosis 36 is secured. Usually, the balloon membrane 4 is inflated once for the same stenosis 36, but it may be inflated multiple times depending on the conditions of the stenosis 36.

Next, another embodiment of the present invention will be described. Second Example This example relates to another method of manufacturing the balloon membrane 4 shown in FIG. Other than the manufacturing method of the balloon membrane 4, the first
The description is omitted because it is the same as the embodiment.

In this embodiment, as shown in FIG. 6, the second parison 30 is attached to the outer periphery of the central portion of the first parison 28, and both ends are reduced in diameter by bonding or heat-sealing them. Prepare parison 4b. Parison 4b
Have, as a result, the same dimensions as the parison 4a shown in FIG.

After that, as in the case of the first embodiment, FIG.
The balloon film 4 shown in can be formed. Third Embodiment In this embodiment, a balloon membrane is manufactured by a method similar to the conventional method, and then the outer periphery of the tubular distal end portion and the tubular proximal end portion of the balloon membrane is mechanically cut, or the tubular membrane of the balloon membrane is shaped. Thinning is performed by a method in which the distal end portion and the cylindrical proximal end portion are heated and passed through a molding die. Even with such a method, the balloon membrane 4 shown in FIG. 2 according to the first embodiment.
Can be manufactured.

The other manufacturing method and structure are the same as those in the first embodiment. Fourth Embodiment The balloon catheter 2A according to the embodiment shown in FIG. 7 is different from the balloon catheter 2 of the embodiment shown in FIG. 1 only in the bonding structure of the balloon membrane 4A, the inner tube 10A and the distal end portions thereof. And other configurations are the same.
Therefore, the members common to the balloon catheter 2 of the embodiment shown in FIG. 1 are designated by the same reference numerals, and the description thereof is partially omitted. The materials and dimensions of the balloon membrane 4A and the inner tube 10A are the same as those in the above-mentioned first embodiment except for the special notes below.

In the balloon catheter 2A of this embodiment,
Similar to the balloon membrane shown in FIG. 2, the balloon membrane 4A should be formed thinner than the conventional one so that the distal end portion 7b and the proximal end portion 5b thereof satisfy the above formulas (1) and (2). Is preferred. However, in this embodiment, since that portion is not the point, the distal end portion 7b and the proximal end portion 5b of the balloon film 4A may have the same film thickness as the conventional one.

In this embodiment, as shown in FIGS. 8 (A) and 8 (B), the outer diameter of the distal end portion 70 of the inner tube 10A is set to the other portion (the central portion of the balloon membrane 4A shown in FIG. 7). The inner diameter is smaller than the outer diameter of the inner tube 10A). Since the guide wire is inserted through the inner diameter of the inner tube 10A,
It is preferably substantially constant in the axial direction. Therefore, the thickness of the tip portion 70 of the inner pipe 10A is smaller than that of the other portions.

The inner diameter of the inner tube 10A is, for example, 0.15 to 1.00 mm, preferably 0.25 to 0.60 mm, as in the case of the first embodiment. The wall thickness of the inner tube 10A other than the tip portion 70 is 0.05 to 0.15 mm,
The wall thickness at the tip portion 70 is preferably 30 to 70% with respect to the wall thickness other than the tip portion 70, specifically, 0.05.
.About.0.10 mm is preferred.

The reduced diameter tip portion 70 of the inner pipe 10A
The length L ₂ of the balloon membrane is equal to the tip portion 7b of the balloon membrane 4A shown in FIG.
The length is preferably the length corresponding to the connecting portion with or, or is longer than that, specifically, 2 to 20 mm is preferable. As a means for reducing the diameter of the distal end portion 70 of the inner pipe 10A, mechanical cutting, drawing drawing using a forming die and a mandrel, extrusion drawing, or the like can be used.

In the balloon catheter 2A according to this embodiment, only the outer diameter of the distal end portion 70 of the inner tube 10A is reduced to a small diameter, and the distal end portion 7b of the balloon membrane 4A is adhered or heat fused to that portion. Because there is a balloon catheter 2
The outer diameter of the tip portion of A becomes smaller. Further, the distal end portion 70 of the inner tube 10A becomes thin, and the flexibility of that portion is improved.
As a result, in the balloon catheter 2A of the present embodiment, even if the stenosis part is eccentric to the blood vessel or the meandering stenosis part, the distal end of the balloon catheter 2A is flexibly bent, so that the balloon catheter 2A can be easily guided along the guide wire. Can be pushed to.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the present invention. For example, in each of the above embodiments, the case where the balloon catheter according to the present invention is used for the PTCA treatment method has been described as an example, but the balloon catheter according to the present invention expands a blood vessel in which a stenosis or the like is formed or other body cavity. It can be widely used for

Next, the present invention will be described more specifically, but the present invention is not limited to these examples. Example 1 and Comparative Example 1 A balloon of nylon 11 was used to form a balloon.

The linear elastic modulus of the nylon 11 used is about 45.
It was 00 kg / cm. Perform mechanical cutting of both end portions as shown in FIG. 10, R _l is 1.125mm, R _s = R _s 'is 1.072mm, R _d is 0.325 mm, t _s' is = t _s 0.374mm , T _l was 0.4 mm, La was 40 mm, Lb was 30 mm, and Lc was 20 mm.

This tube was put in a mold, and the temperature was 184 ° C. and 7 kg.
A balloon film was formed by applying heat and pressure at a pressure of about 10 cm ² / cm ² . After molding, the tip and the hand were cut using a cutting machine. The balloon membrane after cutting (Example 1) had an outer diameter of 3 mm at the center, a thickness of 0.1 mm, and an outer diameter of 1.2 at the tip.
mm, the wall thickness became 0.30 mm. The dimensions of the proximal portion were an outer diameter of 1.36 mm and a wall thickness of 0.23 mm. The balloon membrane (Comparative Example 1) after being molded in the same manner as described above, except that both ends were not cut after being heated and pressed in the mold, had a tip end outer diameter of 1.42 mm and a wall thickness of 0. .42 mm, the outer diameter of the proximal portion was 1.60 mm, and the wall thickness was 0.35 mm.

The two types of balloon membranes (Example 1 and Comparative Example 1) were connected to catheter tubes each consisting of a polyethylene outer tube and an inner tube. The linear elastic modulus of the polyethylene used was about 1000 kg / cm 2. The inner tube connected to the tip of the balloon membrane has an outer diameter of 0.6 mm and a wall thickness of 0.08 mm, and the outer tube connected to the proximal end has an outer diameter of 0.9 mm and a wall thickness of 0.08 mm. It was the one. Elastic polyurethane rubber was used as the adhesive.
In this embodiment, R _l × t _l −t _l ² = 0.
29 and 0.9 (R _s × t _s −t _s ² ) = 0.24
3 and the formula R _l × t _l −t _l ² ≧ 0.9 (R _s × t _s −t _s ² ). ． ． The condition (1) is satisfied.

On the other hand, in Comparative Example 1, R _l × t _l −t _l ²
= A _{0.29, 0.9 (R s × t} s -t s 2) =
It is 0.378, which does not satisfy the above formula (1). Next, an experiment in which the balloon catheters of Example 1 and Comparative Example 1 were inserted into a polyvinyl chloride hard tube created by simulating a blood vessel by bending it to an inner diameter of 2.5 mm and a radius of curvature of 10 mm immersed in warm water was tested. went.

The results of 10 trials are shown below.

[0064]

[Table 1]

As shown in the above table, this difference is due to the size of the balloon tip, especially the tip wall thickness. In Example 1 and Comparative Example 1, the difference in wall thickness in the vicinity of the tip is small, but when the tube is inserted into a hard tube simulating a blood vessel strongly distorted with a radius of curvature of 10 mm, the catheter tip in this example is The rigidity of is low due to structural mechanics.

Under the condition that the transmission of the pushing force is limited by the soft catheter tube, it is considered that there is a difference in ease of insertion between the present Example 1 and Comparative Example 1. In actual clinical practice, the inner diameter of the blood vessel may be significantly narrowed, and at that time, it is considered that the small outer diameter of the balloon tip according to the present embodiment is also advantageous for the catheter insertability.

Example 2 In the tube shown in FIG. 10, R ₁ was 1.125 mm,
R _d is 0.325 mm, t _s = t _s ' is 0.346 mm, t
A tube of nylon 11 having a size of _l = 0.4 mm and R _s = R _s ′ of 1.017 mm was prepared. Using this tube, a balloon film was formed in the same manner as in Example 1, and both ends were cut after forming. The tip of the balloon, the center,
The outer diameter and wall thickness on the proximal side are 1.13 mm (outer diameter) /
0.27mm (wall thickness), 3.00mm (outer diameter) /0.10mm
(Wall thickness), 1.32 mm (outer diameter) /0.21 mm (wall thickness). In this embodiment, R _l × t _l −t _l ² =
Is _{2.9, 0.9 (R s × t} s -t s 2) = 0.2
0897, and the formula R _l × t _l −t _l ² ≧ 0.9 (R _s × t _s −t _s ² ). ． ． The condition (1) is satisfied. This balloon membrane was connected to the catheter shown in Example 1, and insertion into the simulated blood vessel shown in Example 1 was tried 10 times. Table 2 shows the results.

[0068]

[Table 2]

Examples 3 and 4 and Comparative Example 2 Nylon 11 tubes as shown below were prepared,
A balloon membrane was molded. The linear elastic modulus of the nylon 11 used was about 4500 kg / cm 2. Both ends of the tubes of Examples 3 and 4 were mechanically cut to have a predetermined outer diameter as illustrated in FIG.

After placing these tubes in a mold and heating and pressurizing them in the same manner as in Example 1 to form a balloon, the tip portion and the hand portion are cut using a cutting machine to give a predetermined outer diameter and wall thickness. And In all of the balloon membranes, the outer diameter of the central portion of the balloon was 3.0 mm and the wall thickness at that portion was 0.16 mm.

A die for molding the balloon membrane of Example 3 was used.
The tube size is R in FIG. _lIs 1.37 mm, R
_s= R_s'1.073 mm, R_dIs 0.325 mm, t_s
= T _s'Is 0.374 mm, t_lIs 0.53 mm. Success
The outer diameter of the balloon central portion of the shaped balloon membrane is 3.0 mm,
The wall thickness is 0.16 mm, the outer diameter is 1.20 mm at the tip, and the wall thickness is
0.30 mm, outer diameter 1.36 mm at hand, wall thickness 0.23
mm. In this embodiment, R_l× t_l-T_l ²=
0.4544 and 0.9 (R_s× t_s-T_s ²) =
0.243 and the formula R_l× t_l-T_l ²≧ 0.9 (R_s× t_s-T_s ²). ． ． The condition (1) is satisfied. Mold the balloon membrane of Example 4
The tube size for the purpose is R in FIG. _lIs 1.
39 mm, R_s= R_s'1.31mm, R_dIs 0.325
mm, t_s= T _s'Is 0.495 mm, t_lIs 0.53 mm
Is. The outer diameter of the balloon central part of the balloon membrane after molding is
3.0mm, wall thickness 0.16mm, outer diameter 1.4 at the tip
1mm, wall thickness 0.40mm, outer diameter at hand is 1.56mm, meat
The thickness is 0.33 mm. In this embodiment, R_l× t_l
-T_l ²= 0.4544 and 0.9 (R_s× t_s−
t_s ²) = 0.3636, the formula R_l× t_l-T_l ²≧ 0.9 (R_s× t_s-T_s ²). ． ． The condition (1) is satisfied.

Comparative Example 2 was the same as Example 4 except that both ends were not cut after heating and pressurizing in the mold, the outer diameter of the central portion of the balloon was 3.0 mm, the wall thickness was 0.16 mm, and the tip was A balloon membrane having an outer diameter of 1.57 mm and a wall thickness of 0.48 mm was formed in the portion, and an outer diameter of 1.71 mm and a wall thickness of 0.40 mm was formed in the proximal portion.

In this comparative example, R _l × t _l −t _l ²
= 0.4544, and 0.9 (R _s × t _s −t _s ² ).
= 0.47088 and the formula R _l × t _l −t _l ² ≧ 0.9 (R _s × t _s −t _s ² ). ． ． The condition of (1) is not satisfied. These types of balloon membranes were connected to a polyethylene catheter tube as in Example 1.

The polyethylene used has a linear elastic modulus of about 10
It was 00 kg / cm. The inner tube connected to the balloon tip has an outer diameter of 0.6 mm and a wall thickness of 0.08 mm. The outer tube connected to the proximal end of the balloon has an outer diameter of 0.9 mm.
The thickness was 0.08 mm. Elastic polyurethane rubber was used as the adhesive.

Next, the balloon catheters of these Examples and Comparative Examples are inserted into a polyvinyl chloride hard tube which is soaked in warm water and bent to an inner diameter of 2.5 mm and a radius of curvature of 10 mm to imitate a blood vessel. An experiment was conducted. 10 each
The results of the trials are shown in Table 3.

[0076]

[Table 3]

As shown in Table 3, a large difference was found in the insertion characteristics between the example and the comparative example. This difference is due to the size of the balloon tip, especially the wall thickness. In the example and the comparative example, the difference in wall thickness near the tip is only 0.08 mm,
In this embodiment, the rigidity of the tip of the catheter is low when it is inserted into a hard tube that imitates a blood vessel with a curvature radius of 10 mm and is strongly distorted.

Under this condition where the transmission of the pushing force is limited by the soft catheter tube, it is considered that Example 4 had a difference in ease of insertion as compared with the comparative example. Example 3 was particularly excellent for the same reason. In actual clinical practice, the inner diameter of the blood vessel may also be significantly narrowed. At that time, it is considered that the small outer diameter of the balloon tip according to this embodiment also has an advantageous effect on the catheter insertability.

[0079]Example 5 and Comparative Example 3 The method of passing the tube through the heated die is shown in FIG.
_lIs 1.125 mm, R _s’= R_sIs 1.017 mm, R_d
Is 0.325 mm, t_s= T_s'Is 0.346 mm, t_lBut
A 0.4 mm nylon 11 tube was made.

Using this tube, heat and pressure molding was carried out in a mold in the same manner as in Example 1, and then the tip portion and the hand portion were cut by a cutting machine to form a balloon film. The outer diameter and wall thickness of the balloon membrane at the tip, center, and proximal sides are 1.13 mm each.
(Outer diameter) /0.27 mm (wall thickness), 3.00 mm (outer diameter) /
0.10 mm (wall thickness), 1.32 mm (outer diameter) /0.21 mm
It became (thickness). In this embodiment, R _l × t _l −
t _l ² = 0.29, and 0.9 (R _s × t _s −
t _s ² ) = 0.209, and the equation R _l × t _l −t _l ² ≧ 0.9 (R _s × t _s −t _s ² ). ． ． The condition (1) is satisfied. The polyethylene catheter tube shown in the above Examples 3 and 4 was connected to this.

As a comparative example, a balloon membrane formed without reducing the thickness of both ends (without cutting) was similarly connected to the polyethylene catheter tube. The outer diameter and the wall thickness are 1.48 for the tip, center, and hand.
mm (outer diameter) /0.44 mm (wall thickness), 3.00 mm (outer diameter)
/0.10mm (wall thickness), 1.64mm (outer diameter) /0.37
mm (thickness).

In the comparative example, R _l × t _l −t _l ² =
Is _{0.29, 0.9 (R s × t} s -t s 2) = 0.
412 and the formula R _l × t _l −t _l ² ≧ 0.9 (R _s × t _s −t _s ² ). ． ． The condition of (1) is not satisfied. Insertion of these catheters into the simulated blood vessels used in Example 3 etc. was tried 10 times each. The results are shown in Table 4.

[0083]

[Table 4]

Example 6 Only the tip portion of a tube having an outer diameter of 0.6 mm and a wall thickness of 0.08 mm was reduced in diameter by cutting or the like to give an outer diameter of 0.52 mm and a wall thickness of 0.0.
4mm (outer diameter 0.6mm, wall thickness 0.0
8 mm), the inner tube of the balloon catheter was molded.

Apart from this, in the same manner as in Example 4,
R shown in 10_lIs 1.39 mm, R_s= R_sIs 1.31m
m, R_dIs 0.325 mm, t_s= T_s’Is 0.495 m
m, t _lA tube of 0.53 mm is formed by cutting
did. After heat and pressure molding this tube in a mold,
Machined and cut, balloon membrane tip, center and hand
Is 1.37mm (outer diameter) /0.43mm (wall thickness),
3.00 mm (outer diameter) /0.16 mm (wall thickness), 1.56 mm
(Outer diameter) /0.33mm (wall thickness) balloon membrane is formed
It was

This balloon membrane was connected to an inner tube (a tube having a tapered tip of the inner tube) and an outer tube (same as in Example 1) of the balloon catheter, and a catheter was assembled in the same manner as in Example 1, The test was conducted in the same manner as in Example 1. The results are shown in Table 5.

[0087]

[Table 5]

In this embodiment, the outer diameter of the distal end of the balloon is 0.0 compared to that in the fourth embodiment because the inner tube is reduced in diameter.
It is 4 mm (about 3%) thinner. This is expected to have good penetrability when applied to a narrowed blood vessel in actual clinical practice.

[0089]

As described above, according to the present invention, when the stenosis formed in a body cavity such as a blood vessel is narrow, the stenosis is hard, or the stenosis is eccentric or meandering, The balloon membrane of the balloon catheter can be easily and accurately advanced to the position of the narrowed portion of the body cavity with low operating force, and the function of expanding the body cavity of the balloon catheter can be effectively exhibited.

In the method for manufacturing a balloon catheter according to the present invention, the thickness of the distal end portion of the balloon membrane can be thinned without lowering the pressure resistance of the balloon membrane at the central portion of the balloon membrane.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a balloon catheter according to an embodiment of the present invention.

2 is a cross-sectional view of a balloon membrane used in the balloon catheter shown in FIG.

3 (A) and 3 (B) are perspective views showing a parison for producing the balloon membrane shown in FIG.

FIG. 4 is a schematic view showing a method of using the balloon catheter shown in FIG.

5 (A) to (C) are cross-sectional views of a main part showing a method of using the balloon catheter shown in FIG.

FIG. 6 is a cross-sectional view of a parison for manufacturing a balloon membrane of a balloon catheter according to another embodiment of the present invention.

FIG. 7 is a schematic sectional view of a balloon catheter according to another embodiment of the present invention.

8 (A) and 8 (B) are a perspective view and a cross-sectional view of a main part of a distal end portion of the inner pipe shown in FIG. 7.

FIG. 9 is a cross-sectional view of a balloon membrane used in a balloon catheter according to a conventional example.

FIG. 10 is a perspective view showing dimensions of a parison for manufacturing a balloon membrane of a balloon catheter according to an example of the present invention and a comparative example.

[Explanation of symbols]

 2, 2A ... Balloon catheter 4, 4A ... Balloon membrane 5, 5b ... Proximal end portion 6 ... Catheter tube 7, 7b ... Tip portion 8 ... Branch portion 10, 10A ... Inner tube 12 ... Second lumen 14 ... First lumen 20 ... Open end 22 ... Balloon membrane central part 24, 26 ... Tapered part 32 ... Guide catheter 34 ... Aorta 36 ... Stenosis part

Claims (3)

[Claims] 1. A balloon catheter for body cavity expansion having a tubular balloon membrane for expanding a flow channel in the body cavity by being inserted into a body cavity such as a blood vessel and inflated, wherein the distal end of the tubular balloon membrane is provided. When the outer diameter of the portion and the outer diameter of the central portion are R _s and R _l , respectively, and the film thicknesses of the tip portion and the central portion of the tubular balloon membrane are t _s and t _l , respectively, these R _s , R _l , t _s and t
_A balloon catheter for body cavity dilation, wherein the relationship of _l satisfies the following expression (1). [Formula 1] R _l × t _l −t _l ² ≧ 0.9 × (R _s × t _s −t _s ² ) ... (1) 2. A step of preparing a tubular parison having a thicker film thickness at a central portion with respect to a film thickness at both end portions, and a step of blow molding this parison to form a cylindrical balloon membrane central portion having a large outer diameter. And a step of forming a balloon membrane having a tubular distal end portion and a proximal end portion each having a small outer diameter and located at both ends thereof. 3. A balloon membrane that expands a channel in a body cavity by being inserted into a body cavity such as a blood vessel and inflated, and a distal end is connected to a proximal end of the balloon membrane, and a fluid is introduced into the inside of the balloon membrane. A catheter tube having a first lumen formed therein to inflate the balloon part and an open end formed at the tip part, and the tip part of the balloon membrane is connected to the outer circumference of the tip part. A balloon catheter for expanding a body cavity, which has an inner tube extending in the axial direction inside a catheter tube and having a second lumen formed therein, the outer diameter of the distal end portion of the inner tube to which the distal end portion of the balloon membrane is connected. However, the balloon catheter for body cavity dilation has a diameter smaller than the outer diameter of the inner tube located in the center of the balloon membrane.