JP2002291897A - Balloon catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a balloon catheter that secures the stiffness of a catheter tube, is kink resistant, flexibly deforms in response to the bending portion of a blood vessel and especially has 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 is formed along the longitudinal direction, a balloon portion 4 in which the proximal end of the balloon portion 4 is jointed to the distal end of the external tube 6, and the balloon expansion lumen and the interior communicate, and an internal tube 12 in which the distal end of the balloon portion 4 is jointed to its distal end and extends to the interior of the balloon portion 4 and the interior of the balloon expansion lumen of the external tube 6 in the axial direction so that a tightly closed expansion space may be formed in the interior of the balloon portion 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balloon catheter suitably used as, for example, a balloon catheter for dilating blood vessels, and more particularly to an improvement of a so-called monorail type balloon catheter.

[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, there are an over-the-wire balloon catheter and a monorail balloon catheter. 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. At that time, the dilation of the stenosis needs to be performed stepwise so as not to damage the blood vessel, and at first, insert a balloon catheter with a balloon part with a small outer diameter along the guide wire,
The balloon catheter is sequentially replaced with a balloon catheter having a larger outer diameter balloon portion.

In an over-the-wire balloon catheter, a guide wire lumen is formed over the entire length of the catheter tube, a guide wire is inserted through the lumen, and a balloon portion is formed along the guide wire. Guide to the stenosis. Then, after performing a blood vessel dilation with a balloon catheter having a balloon portion having a smaller outer diameter, the balloon catheter is replaced with a balloon catheter having a balloon portion having a larger outer diameter. At that time, since the balloon catheter is withdrawn along the guide wire, it is necessary that the proximal end of the guide wire extends to the outside of the body for more than the entire length of the catheter tube. Otherwise, the balloon catheter cannot be replaced while leaving the distal end of the guidewire in the stenosis.

On the other hand, for example, Japanese Patent Application Laid-Open No. Sho 63-28
In the monorail type balloon catheter disclosed in JP-A-8167 and JP-A-2-307479, an opening is formed in the middle of the catheter tube, and the opening is formed from the opening through the guide wire insertion lumen to the distal end of the balloon. Leading. Therefore, in this type of balloon catheter, the length of the guide wire extending outside the body for replacement of the balloon catheter may be slightly longer than the length corresponding to the length from the opening to the distal end of the balloon. , Compared to other systems. Therefore, the operability is excellent.

Further, such a monorail type balloon catheter is disclosed in US Pat. No. 4,762,129, US Pat.
No. 276411 and JP-A-6-506124.

However, in the balloon catheter disclosed in JP-A-63-288167 and JP-A-2-307479, a double-lumen tubular member having two lumens is provided from the proximal end to the distal end of the catheter tube. The middle of one of the lumens is sealed with an adhesive or the like, a side hole is opened at the distal end side of the sealed portion, and a monorail type guidewire insertion lumen is formed. Therefore, there is an unnecessary lumen that does not pass through the guide wire inside the catheter tube at the proximal end side of the side hole, which causes an increase in the outer diameter of the catheter tube.

Further, the sealing portion near the side hole formed in the middle of the double-lumen catheter tube needs to be sealed by injecting an adhesive or by pushing in an appropriate plug or the like. Not easy to manufacture.
Further, the catheter tube has a problem that the catheter tube is hard at the sealing portion, and the bending rigidity changes abruptly at the opening portion of the adjacent side hole, so that the catheter tube is easily kinked (bent). Such a phenomenon becomes more pronounced when the reinforcing rod is inserted into the inside of the catheter tube from the sealing portion toward the proximal end, and the catheter tube is more likely to kink. This is because stress tends to concentrate on the notch opening.

In the balloon catheter disclosed in US Pat. No. 4,762,129, an expansion tubular member formed with a balloon expansion lumen and a wire tubular member formed with a guide wire insertion lumen are axially connected. The proximal end neck portion of the balloon portion is joined so as to overlap at a predetermined distance along and along a part of the overlapping portion. But,
In the balloon catheter disclosed in this publication, the outer diameter of the expanding tubular member extending from the proximal end to the proximal end of the balloon portion is extremely thin as compared with the overlapping portion with the wire tubular member, and the kink is easily kinked. Have.

In the balloon catheter disclosed in US Pat. No. 5,061,273, an expansion tubular member having a balloon expansion lumen formed at a position closer to the proximal end than the proximal end of the balloon portion. And a tubular member for a wire, on which a guide wire insertion lumen is formed, is overlapped at a predetermined distance in the axial direction. For this reason, the outer diameter of the overlapping portion becomes large, and there is a problem in the insertion characteristics. If the outer diameter of the expansion tubular member located at a position closer to the proximal end than the overlapping portion is reduced in order to reduce the outer diameter of the overlapping portion, there is a problem in that kink is also likely to occur.

Further, in the balloon catheter disclosed in JP-A-9-276411 and JP-A-6-506124, the ends of two tubular members constituting a catheter tube are covered with another tubular member. As a result, the outer diameter of the portion becomes large in a step-like manner, and there is a problem in ease of insertion of the balloon catheter.

[0012] Furthermore, Japanese Patent Publication No. 9-503411 discloses that a reinforcing rod is disposed between the proximal end of the catheter tube and the proximal end of the balloon portion in order to improve the pushing characteristics of the catheter tube. A balloon catheter having a distal end fixed to a catheter tube has been proposed. However, this balloon catheter has a problem that it is difficult to push the balloon catheter into a complicated and meandering blood vessel because the flexibility of the distal end portion of the catheter tube is reduced.

[0013]

Therefore, the present applicant has
As disclosed in Japanese Patent Application Laid-Open No. 2000-217923, manufacture is easy, the outer diameter of the catheter tube is easily reduced, the outer shape from the proximal end to the distal end of the catheter tube has no step, and the insertion of the balloon catheter is performed. We have proposed a balloon catheter that is excellent in characteristics and excellent in push-in characteristics that are difficult to kink.

In the balloon catheter disclosed in this publication, metal reinforcement is provided from the proximal end to the vicinity of the distal end of the catheter tube so that the catheter tube can be smoothly inserted into a blood vessel while securing the rigidity of the catheter tube. A rod may be built in.

In this case, conventionally, the reinforcing rod is fixed using an adhesive or the like in an inner lumen formed in the catheter tube along the axial direction, and the distal end of the reinforcing rod is also connected to the catheter tube. Was fixed to the lumen inner wall.

However, catheters used for applications such as PTCA have a large number of bifurcations and are used for thin blood vessels such as coronary arteries. Therefore, the distal end of a metal reinforcing rod is fixed to the inner wall of a catheter tube. May be difficult to deform flexibly in response to the bent part of the blood vessel,
Particularly in the vicinity of the distal end of the catheter tube where flexibility is required, structural improvement has been required.

The present invention has been made in view of such circumstances, and an object of the present invention is to secure the rigidity of a catheter tube, to prevent kinking, and to flexibly deform in accordance with a bent portion of a blood vessel. In particular, it is an object of the present invention to provide a balloon catheter having excellent insertion characteristics and pushing characteristics.

[0018]

In order to achieve the above object, a balloon catheter according to the present invention comprises an outer tube having at least one lumen for expanding a balloon formed along a longitudinal direction, and A proximal end portion of the balloon portion joined to the distal end portion, a balloon portion communicating with the balloon inflation lumen, and a balloon portion so as to form a sealed inflation space inside the balloon portion; A distal end of the inner tube is joined to a distal end of the inner tube, and the inner tube extends axially inside the balloon portion and inside the balloon expansion lumen of the outer tube. An inner tube wherein the proximal end opening of the inner tube is open to the outside through a tube wall positioned halfway in the longitudinal direction of the outer tube; and A stiffening rod extending from a proximal end of the outer tube to a position beyond the proximal end opening of the inner tube, wherein the distal end of the stiffening rod is positioned relative to the inner wall of the outer tube. It is characterized by not being fixed.

Preferably, the outer tube has a first outer tube member and a second outer tube member joined to a proximal end of the first outer tube member, wherein a proximal end of the inner tube is provided. An opening is open to the outside through a tube wall positioned halfway in the longitudinal direction of the first outer tube member.

Preferably, in addition to the balloon expansion lumen, a rod lumen through which a proximal end portion of the reinforcing rod is inserted is formed in the second outer tube member. The distal end portion is fixed to the inner wall of the rod lumen by an adhesive.

Preferably, the reinforcing rod extends over a predetermined length from the joint between the first outer tube member and the second outer tube member toward a proximal end, and the inner wall of the rod lumen has a predetermined length. It has a part that is not fixed to.

Preferably, the distal end of the reinforcing rod projects from the distal end opening of the rod lumen of the second outer tube member into the balloon inflation lumen of the first outer tube member. ing.

[0023]

In the balloon catheter according to the present invention, only the distal end of the balloon catheter adopts a so-called coaxial catheter tube structure composed of an outer tube and an inner tube, and the lumen of the inner tube is inserted through a guide wire. We use as lumen. For this reason, the balloon catheter according to the present invention has an outer diameter of the catheter tube in comparison with a conventional balloon catheter having a so-called double-lumen catheter tube (Japanese Patent Laid-Open Nos. 63-288167 and 2-307479). Is easy to make thin. Further, in the balloon catheter according to the present invention, the proximal end opening of the inner tube serving as the proximal end side take-out port of the guide wire is opened to the outside through the tube wall located in the middle of the outer tube in the longitudinal direction. The opening has a double structure of an inner tube and an outer tube, and has a structure that is difficult to kink.

Further, in the balloon catheter according to the present invention, the proximal end opening of the inner tube, which serves as the proximal end side outlet of the guide wire, penetrates the tube wall located in the longitudinal direction of the outer tube and extends outside. Since there is no need to make a step over the entire length of the catheter tube, the balloon catheter has excellent insertion characteristics. In addition, since it has a structure that does not easily kink, the balloon catheter has excellent pushing characteristics.

In the present invention, the reinforcing rod extending to the vicinity of the proximal end opening of the inner tube is disposed on the proximal end side of the outer tube constituting the catheter tube.
The catheter tube of the present invention has a structure that is particularly difficult to kink. Further, the pushing force from the proximal end of the catheter tube is easily transmitted to the proximal end side of the catheter tube, and the operability and the pushing characteristics are excellent.

In particular, in the present invention, since the distal end of the reinforcing rod is not fixed to the inner wall of the outer tube constituting the catheter tube, the balloon catheter can be used for a blood vessel having many branches and a thin blood vessel such as a coronary artery. Even when inserted, the distal end of the outer tube deforms flexibly corresponding to the bent portion of the blood vessel. This is because the distal end of the outer tube is not fixed to the inner wall of the outer tube, so the distal end of the outer tube is not limited to the reinforcing rod,
It is thought that it can be deformed freely. Therefore, in the balloon catheter of the present invention, the insertion characteristics and the pushing characteristics of the balloon catheter are improved.

Further, in the present invention, the outer tube is formed of a relatively flexible distal end first outer tube member and a relatively rigid proximal end side outer tube member joined to the first outer tube member. By using the two outer tube members, the push-in characteristics of the balloon catheter 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.

[0028]

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 a method 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, and a connector 8.

The balloon portion 4 shown in FIGS. 1 and 4 is formed of a cylindrical film having both ends reduced in diameter.
Although not particularly limited, 10 to 300 μm, preferably 2 μm
0 to 150 μm. The balloon portion 4 is not particularly limited as long as it is cylindrical, and may have a cylindrical or polygonal cylindrical shape.
The outer diameter of the balloon portion 4 at the time of expansion is determined by factors such as the inner diameter of the blood vessel, and is usually about 0.7 to 10.0 mm, preferably 1 to 5 mm. The axial length of the balloon portion 4 is determined by factors such as the size of the intravascular stenosis, and is not particularly limited.
m, 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 constituting the balloon portion 4 is preferably a material having a certain degree of flexibility. For example, ethylene such as polyethylene, polyethylene terephthalate, polypropylene, ethylene-propylene copolymer and other α-olefins may be 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.

As shown in FIG. 4, a proximal end portion 5 of the balloon portion 4 is joined to the outer periphery of the distal end portion of the outer tube 6 by means such as heat fusion or adhesion. The first lumen 10 communicates with the internal expansion space of the balloon section 4. The distal end 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 the first lumen. Other than 10, it is sealed to the outside. The first lumen 10 of the outer tube 6 feeds a fluid into the internal expansion space of the balloon portion 4 to expand the balloon portion 4 or to extract fluid from the expansion space of the balloon portion 4 to contract the balloon portion 4. It is a passage.

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 distal end side first lumen 10 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 its distal end opening 20 opens at the distal end 7 of the balloon section 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 peripheral edge of the proximal end opening 22 of the inner tube 12 and the peripheral edge of the through hole 21 in the tube wall of the outer tube 6 are hermetically joined by a heat fusion method described later. The shape of the proximal end opening 22 of the inner tube 12 is not particularly limited, and may take various shapes such as a circle and an ellipse. In the present embodiment, as shown in FIG. It is an elliptical shape with the part cut diagonally. Inner tube 12
The second lumen 14 is a guide wire insertion lumen through which a guide wire 42 shown in FIG. 4 for guiding the balloon catheter 2 into a body cavity is inserted. Guide wire 4
2 is composed of a single wire or a stranded wire of, for example, stainless steel, copper, copper alloy, titanium, nickel-titanium alloy, and the outer diameter thereof is not particularly limited.
0.1-1 mm, more preferably 0.25-0.6 m
m.

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 that of 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 0.03 to 0.5 mm, more preferably 0.05 to 0.2 mm.

The outer diameter of the inner tube 12 is determined so as to form a gap 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.

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 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 the present 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, is tapered from the middle to the distal end side (taper length 150 to 250 mm), and has a flat cross section at the distal end. Thus, the cross-sectional shape is gradually changing. As shown in FIGS. 1 and 4, the distal end 28a of the reinforcing rod 28 having a flat cross section slightly closes the proximal end opening 22 of the inner tube 12 (usually L3 = 1).
(0 to 100 mm, preferably about 50 to 80 mm), and its distal end 2a is not fixed to the inner wall of the first outer tube member 6a.

In this 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 thereof.
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 outer diameter.
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.
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 covering material. However, when it is not always preferable that the balloon portion slides with respect to the stenotic portion when expanding the stenotic portion, 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, cellulose-based polymer substances (eg, hydroxypropyl cellulose) and polyethylene oxide-based 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. As shown in FIG. 5A, first, a first outer tube member 6a and a balloon portion 4 are prepared, and a cylindrical proximal end portion of the balloon portion 4 is provided on the outer periphery of a distal end of the first outer tube 6a. 5 and heat-sealing the portion. Next, 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 described later can pass through. Also, a heat sealing tube 50 shown in FIG. 5B is prepared. The inner diameter of the heat sealing tube 50 is slightly larger than the outer diameter of the first outer tube member 6a. As the tube 50 for heat sealing, for example, a fluororesin tube is used, and its axial length is, for example, about 20 mm. At one axial end of the heat sealing tube 50,
A cut 52 having a length of about 3 mm is formed.

Next, as shown in FIG. 6A, the inner tube 12 to which the contrast ring 15 is attached is prepared, and the inner tube 12 is integrated with the lumen of the inner tube 12 through the wire-like mandrel 54. The inner tube 12 with the mandrel 54 integrated therethrough 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 7 of the balloon portion 4 to enhance contrast. The ring 15 is located at the center of the balloon section 4. Before and after that, the heat sealing tube 50 is positioned on the outer periphery of the first outer tube member 6a.

Thereafter, the heat sealing mandrel 56 is inserted into the inside from the proximal end of the first outer tube member 6a.
The distal end of the mandrel 56 is positioned near the through hole 21 to prevent the first outer tube 6a from being crushed near the through hole 21. The proximal end of the mandrel 56 has an outer diameter that is substantially equal to or less than the inner diameter of the first outer tube member 6a,
An axial recess 57 is formed at the distal end so as to receive the outer periphery of the inner tube 12. Next, the heat sealing tube 50 is moved in the axial direction around the outer periphery of the first outer tube member 6a, and the heat sealing tube 50 is moved to the outer periphery of the first outer tube 6a near the through hole 21 and the through hole 2
The outer surface of the inner tube 12 that protrudes from the outer tube 1 is integrally covered. Then, using a mold for heat sealing,
Pressing and heating is performed from the outside of the heat sealing tube 50 to thermally fuse the hole edge of the through hole 21 and the outer tube wall of the inner tube 12. The heating temperature is not particularly limited, but is preferably 1
00 to 300 ° C, particularly preferably 150 to 250 ° C
It is.

Thereafter, the mandrels 54 and 56 are taken out, and the notches 5 of the heat sealing tube 50 are cut out.
2 to tear the tube 50 in the axial direction,
Is removed from the outer periphery of the first outer tube 6a. Thereafter, as shown in FIGS. 7A and 7B, a heat-sealed portion between the outer tube wall of the inner tube 12 and the inner edge of the through hole 21 which has been heat-sealed in the heat-sealing step is left. Unnecessary portions of the inner tube 12 located outside the fused portion are cut and removed with a cutter or the like. As a result, the proximal end opening 22 of the inner tube 12
Are formed outside the tube wall of the first outer tube member 6a. The proximal end opening 22 has a substantially elliptical shape in this example. However, in FIG. 7, although the ellipse is considerably flat, it is actually an ellipse close to a circle. In addition,
Before or after these steps, or simultaneously, the distal end of the inner tube 12 shown in FIG. 6A is heat-sealed to the distal end of the balloon 4 by a similar heat sealing method.
It is cut to a predetermined length.

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, as shown in FIG. 8A, the outer periphery of the second outer tube member 6b is made of the same material and structure as the heat sealing tube 50 shown in FIG. The second outer tube member 6 is placed in the lumen at the proximal end of the first outer tube 6a with the sealing tube 58 covered.
Push in the distal end of b. Thereafter, as shown in FIG. 8B, a mandrel 60 is inserted along the axial direction into the third lumen 24 of the second outer tube member 6b, and the tip of the mandrel 60 is inserted into the first outer tube member 6a. Protrude. 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, as shown in FIG. 8C, the heat-sealing tube 58 is moved in the axial direction, and the heat-sealing tube 58 is used to connect the first outer tube member 6a and the second outer tube member 6b. The joint 9 is covered, and heat fusion is performed using a mold under the same heat sealing conditions as those described above.

Thereafter, the heat sealing tube 58 is removed and the mandrel 60 is removed, and 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 the arterial blood vessel, first, a guide wire (not shown) for a guide catheter is inserted into the blood vessel by Seldinger's 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 that is inserted along the guide catheter, and the distal end thereof is inserted to a position passing 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 pulled out of 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 the outer tube 6 and the 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.

Further, in the present 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.

Particularly, 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,
Is not restricted to the reinforcing rod 28,
It is thought that it can be deformed freely.

It should be noted that the present invention is not limited to the above-described embodiment, and 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.

[0071]

As described above, according to the present invention, the rigidity of the catheter tube is ensured, the kink is hardly kinked, and the catheter tube is flexibly deformed corresponding to the bent portion of the blood vessel.
In particular, it is possible to provide a balloon catheter having excellent insertion characteristics and pushing characteristics.

[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. 5A is a perspective view of an outer tube and a balloon portion showing a manufacturing process of the balloon catheter according to the present embodiment, and FIG. 5B is a perspective view of a heat sealing tube used in the manufacturing process of the balloon catheter. FIG.

6 (A) and 6 (B) are perspective views of a main part showing a process of manufacturing a balloon catheter.

7 (A) and 7 (B) are perspective views of a main part showing a manufacturing process of a balloon catheter.

8 (A) to 8 (C) are perspective views of relevant parts showing a manufacturing process subsequent to the process shown in FIG. 7;

[Explanation of symbols]

 2 balloon balloon 4 balloon portion 6 outer 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 28a ... Distal end

Claims (5)

[Claims] 1. An outer tube having at least one balloon inflation lumen formed along a longitudinal direction, and a proximal end of a balloon portion joined to a distal end of the outer tube. A balloon portion that communicates with the lumen, and a distal end portion of the balloon portion is joined to a distal end portion of the inner tube so as to form a sealed expansion space inside the balloon portion; And an inner tube extending axially into the interior of the outer tube and the interior of the balloon-expanding lumen of the outer tube, wherein the proximal end opening of the inner tube is positioned halfway in the longitudinal direction of the outer tube. An inner tube extending through the wall to open to the outside; extending inside the outer tube from a proximal end of the outer tube to a position beyond a proximal end opening of the inner tube. A balloon catheter having a reinforcing rod, wherein a distal end of the reinforcing rod is not fixed to an inner wall of the outer tube. 2. The outer tube has a first outer tube member and a second outer tube member joined to a proximal end of the first outer tube member, wherein a proximal end opening of the inner tube is provided. 2. The balloon catheter according to claim 1, wherein the portion penetrates a tube wall positioned in the longitudinal direction of the first outer tube member and opens to the outside. 3. The second outer tube member further includes a rod lumen through which a proximal end portion of the reinforcing rod is inserted, in addition to the balloon expansion lumen. The balloon catheter according to claim 2, wherein an end portion is fixed to an inner wall of the rod lumen by an adhesive. 4. A reinforcing rod is provided on an inner wall of the rod lumen for a predetermined length from a joint between the first outer tube member and the second outer tube member toward a proximal end side. 4. The balloon catheter according to claim 3, wherein the balloon catheter has a portion that is not fixed. 5. The method according to claim 5, wherein a distal end of the reinforcing rod is the second end.
The balloon catheter according to claim 3 or 4, wherein the balloon catheter protrudes from the distal end opening of the rod lumen of the outer tube member into the balloon expansion lumen of the first outer tube member.