JP2001353225A - Catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catheter capable of relieving a sudden change in rigidity between a base shaft having high rigidity and a flexible tip shaft, having no possibility of damage over the total length and superior in pressure-proof performance. SOLUTION: An expanded catheter 1 has the base shaft 15 having relatively high rigidity, the tip shaft 13 having rigidity lower than the base shaft, an intermediate part 14 for connecting these shafts, a balloon 12 installed in a tip part of the tip shaft so as to be fluidly communicated therewith and a guide wire opening part 141 on the base end side, and has a guide wire lumen for inserting a guide wire, and is formed such that a tip part of the base shaft 15 becomes a base shaft entering part 152 entering the intermediate part 14, the base shaft entering part 152 has a spiral slit, and a distance at which the guide wire opening part 141 is spaced from the tip of the base shaft 15 to the tip side is 0 to 5 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diagnostic tool or a therapeutic tool for performing various treatments in a blood vessel, a dilatation part for treating a stenosis part in a blood vessel, and a method for expanding a stenosis part in a peripheral part of the stenosis part. The present invention relates to a dilatation catheter for improving blood flow.

[0002]

2. Description of the Related Art The emergence of microcatheters has enabled the treatment and diagnosis of microvessels or blood vessels that have been impossible with conventional catheters.
Examples of the microcatheter include a percutaneous transluminal coronary angioplasty catheter (hereinafter, dilatation catheter) used for myocardial infarction or angina. During this angioplasty procedure, the catheter often needs to be replaced. For example, the catheter needs to be replaced when changing the balloon size, diagnosing the vicinity of a stenosis, changing a treatment tool, and the like. One method of catheter replacement is to use a long replacement guidewire. However, the operation of a long wire is time-consuming and cumbersome because it requires two or more operators. "Rapid exchange" type catheters are used to address this problem. In this type, only the distal end portion of the catheter follows the guide wire.

[0003] Specifically, a rapid exchange type catheter described in EP925801A will be described. This catheter is provided with a coil assembly comprising a coil and a transition tube covering the coil, between a metal tube or a high-strength base shaft equivalent thereto and a highly flexible resin tip shaft. It is configured to mitigate sudden changes in stiffness between the base shaft and the flexible tip shaft.

[0004] However, in this catheter, a gap is inevitably formed between the base shaft and the coil disposed on the distal end side of the catheter. This is problematic in that the part is easily damaged and the pressure resistance is inferior. On the other hand, as a method that does not produce such a gap, it is conceivable to extend the base shaft inside the coil and fit them together to improve the strength. However, in this case, the fitting portion between the two becomes inevitably thick,
Not preferred.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to alleviate a sudden change in rigidity between a highly rigid base shaft and a flexible distal shaft, eliminate the possibility of breakage over the entire length, and provide an excellent pressure resistance. It is to provide a rapid exchange type catheter.

[0006]

SUMMARY OF THE INVENTION A dilatation catheter according to the present invention comprises a tubular base shaft having relatively high rigidity, and a tube-shaped distal shaft provided at a distal end side of the base shaft and having lower rigidity than the base shaft. And a tube-shaped intermediate portion that is located between the base shaft and the tip shaft and that connects the base shaft and the tip shaft in a liquid-tight manner, and is attached near the base end of the base shaft, and is a pressure application device. A hub to which is attached is provided so as to be in fluid communication with the distal end of the distal shaft,
A balloon to which pressure is applied from the hub, a guide wire lumen having a distal opening at a distal end from the balloon distal end and a proximal opening at a proximal end from the balloon proximal end, and through which a guide wire is inserted. Wherein the distal end of the base shaft is an intrusion that has penetrated into the intermediate portion, the intrusion has a helical slit, and the guide wire lumen The distance at which the base-side opening is separated from the distal end of the base shaft toward the distal end is within 5 mm (when the base-side opening extends over a predetermined length in the longitudinal direction of the catheter, the base-side opening is The distance at which the distal end is separated from the distal end of the base shaft toward the distal end is within 5 mm).

[0007] A catheter of the present invention comprises a tubular base shaft having relatively high rigidity, a tube-shaped distal shaft provided at a distal end side of the base shaft, and having a lower rigidity than the base shaft; A tube-shaped intermediate portion that is located between the distal shafts and connects the base shaft and the distal shaft in a liquid-tight manner, a hub attached near the proximal end of the base shaft, and a distal end of the distal shaft. Provided treatment device (device for performing treatment such as treatment or diagnosis, such as an ultrasonic diagnostic device, a laser irradiation device, an atherectomy cutter, a drug supply device, a high-frequency generator, and an ultrasonic therapeutic device)
A catheter having a distal opening on the distal side of the treatment device and a proximal opening on the proximal side of the treatment device, and a guide wire lumen through which a guide wire is inserted. The distal end of the base shaft is an intrusion that has penetrated into the intermediate portion, the intrusion has a spiral slit, and the base-side opening of the guidewire lumen of the guidewire lumen The distance at which the part is separated from the tip of the base shaft toward the tip is 5 mm
It is characterized by being within.

In the present invention, the relatively rigid base shaft is preferably formed of a metal tube. In order to form a spiral slit in the vicinity of the tip of the base shaft, generally used techniques such as laser processing (for example, YAG laser), electric discharge processing, chemical etching, and cutting processing can be used. In this case, the pitch of the helical (spiral) slit is formed short at the tip end side of the slit and long at the base end side, so that the rigidity of the base shaft entry portion formed gradually changes. Is also good.

In the present invention, a spiral slit is formed in the base shaft, and the distal end is formed as a base shaft intrusion into the intermediate portion. Over time, it is possible to gradually change the rigidity. In addition, the distance from the distal end of the base shaft to the proximal side opening of the guide wire lumen spaced apart from the distal side is 0 to 5 mm (the proximal side opening extends over a predetermined length in the longitudinal direction of the catheter. The distance from the tip of the base side opening to the tip of the base shaft is in the range of 0 to 5 mm), so that the base side opening,
Alternatively, even if another reinforcing member is not disposed in a portion between the base side opening and the tip of the base shaft, the strength and pressure resistance of the catheter in this portion become sufficient, and the occurrence of kink during the procedure is reduced. It can be effectively prevented.

[0010] In the present invention, the tip of the helical slit is 10 m closer to the base end than the tip of the base shaft.
m.

[0011] In the catheter of the present invention, the tip of the base shaft need only be subjected to spiral slit processing.
The catheter can be assembled without complicated steps,
In addition, the kink can be effectively prevented by the base shaft entry portion. Further, by shortening the pitch of the spiral slit on the distal end side and increasing it on the proximal end side, the kink can be more effectively prevented by devising such that the rigidity of the base shaft entry portion is gradually changed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a dilatation catheter according to the present invention will be described below with reference to the drawings.

FIG. 1 is an external view of one embodiment of the dilatation catheter of the present invention. FIG. 2 is an external view in which a part of the dilatation catheter of FIG. 1 is cut away, a part of a base shaft is omitted, and main constituent members are enlarged. FIG. 3 is an external view showing a base shaft. FIG. 4 is a cross-sectional view showing the intermediate portion, the distal end of the base shaft, and the proximal end of the distal shaft.

As shown in FIGS. 1 and 2, the dilatation catheter 1 is a so-called rapid exchange type catheter, and is inserted into a blood vessel along a guide wire 2. The dilatation catheter 1 includes a hub 16, a base shaft 15, an intermediate portion 14, a distal shaft 13, a balloon 12, and an inner tube shaft 11 from the proximal end side.

A luer taper is formed on the base end hub 16 so that it can be connected to a pressure applying device such as an inflator. A base shaft 15 made of a material having relatively high rigidity such as a metal or some resin is joined to the hub 16 so as to be capable of fluid communication. The base shaft 15 is provided with a depth marker 151 so that the depth at which the dilatation catheter 1 is inserted into the guiding catheter (not shown) during angioplasty can be easily checked.
As will be described later in detail, the distal end portion of the base shaft 15 is a base shaft entry portion 152.

An intermediate portion 1 is provided at the distal end of the base shaft 15.
4 is provided for fluid communication. A relatively rigid distal shaft 13 made of a material such as resin is provided at the distal end side of the intermediate portion 14 so as to be able to communicate with the fluid. The proximal end of the balloon 12 is provided at the distal end of the distal shaft 13 so as to be able to communicate with the fluid.

An inner tube shaft 11 passes coaxially through the inside of the tip shaft 13 and the balloon 12. The distal end of the inner tube shaft 11 is a distal tip 111, and the distal tip 111 is extended from the distal end of the balloon 12. The distal tip 111 is joined to the distal end side of the balloon 12 in a liquid-tight state. I have. On the other hand, the inner pipe shaft 11
Is extended to a guide wire opening 141 provided in a part from the intermediate portion 14 to the distal shaft 13 and is joined in a liquid-tight state. The lumen extending from the distal end of the inner tube shaft to the guide wire opening 141 serves as a guide wire lumen. The guide wire 2 shown in FIG. Is inserted into the inner tube shaft 11 as an outlet. A contrast marker 121 is provided around the inner tube shaft 11 inside the balloon 12.

When the balloon 12 is not expanded, the balloon 12 is folded around the inner tube shaft 11. When the balloon 12 is in the expanded state, the central portion becomes substantially cylindrical and the stenotic part of the blood vessel can be easily expanded. Note that the central portion of the balloon 12 does not need to be completely cylindrical,
It may be in the shape of a polygonal column. In addition, during the angioplasty, the contrast marker 121 displays the balloon 12 to the stenosis site under fluoroscopy.
Is provided to facilitate the positioning of the device.

In the dilatation catheter 1 having the above-described configuration, when a pressure is applied by a pressure application device (not shown) attached to the hub 16, the pressure medium flows from the hub 16 to the base shaft 15, the base shaft intrusion portion 152, and the middle. The balloon 12 can be expanded by reaching the balloon 12 through the gap between the portion 14, the distal shaft 13 and the inner tube shaft 11. In addition, the base shaft 15, the intermediate portion 14,
Needless to say, the distal shaft 13, the inner tube shaft 11, and the respective joints have a pressure resistance performance higher than the pressure at which the balloon 12 bursts.

The structure of the base shaft 15 will be described in more detail with reference to FIG. As shown in FIG. 3, the base shaft 15 includes a main shaft portion 153 and a main shaft portion 1.
53 is formed by a base shaft entry portion 152 formed by subjecting a distal end portion to spiral slit processing. In this figure, the pitch of the spiral slit is short on the distal end side of the slit and long on the base end side, and the pitch between them gradually decreases toward the distal end. Thereby, the pitch of the slits becomes narrower toward the tip. The base shaft entry portion 152 is formed by laser processing the tip of the main shaft portion 153. In the present invention, in addition to the above-described configuration, the pitch of the slit is narrowed toward the front end, for example, the pitch is narrowed at a constant rate from the base to the front end of the slit toward the front end. Is also good.

Referring to FIG. 4, the structure of the distal end of the base shaft 15 and the proximal end of the distal shaft 13 about the intermediate portion 14 is shown. As shown in FIG. 4, the base shaft intrusion portion 152 at the distal end portion of the base shaft 15 is arranged to extend into the intermediate portion 14 and has a configuration in which it enters the intermediate portion 14. The proximal end of the inner tube shaft 11 is fixed to a part of the intermediate portion 14 in the outer peripheral direction, and the proximal opening of the inner tube shaft 11 is
A guide wire opening 141 is formed so as to be exposed to the outside. The guide wire opening 141 may be provided on the distal shaft 13, or may be provided at a boundary (joining portion) between the intermediate portion 14 and the distal shaft 13.

By arranging the base shaft penetration portion 152 inside the intermediate portion 14 in this manner, the intermediate portion 14 has lower rigidity (softer) than the main shaft portion 153, and
The rigidity can be higher (harder) than the tip shaft 13. In this manner, the rigidity of the shaft constituting the dilatation catheter 1 can be gradually changed from the proximal side to the distal side, so that even when the intermediate portion 14 bends sharply, stress does not concentrate on one place, and the It is possible to reduce the occurrence.

As described above, according to the present invention, the base shaft 15 (main shaft portion 153) of the dilatation catheter 1 is provided.
By performing a spiral slit process using a commonly used technique such as laser processing on the vicinity of the front end of the base shaft, a base shaft intrusion portion 152 serving to prevent kink is formed. In this simple process, the main shaft 1
The base shaft penetration portion 152 integrated with the catheter shaft 53 can be formed, and the assembly process of the catheter can be simplified as compared with the related art. Then, the base shaft entry portion 15
By arranging 2 inside the intermediate portion 14, even when the intermediate portion 14 is sharply bent, stress does not concentrate at one place, and the occurrence of kink can be effectively reduced. Further, by making the pitch of the spiral slit shorter on the distal end side and longer on the proximal end side, the rigidity of the entire shaft can be gradually changed, and the occurrence of kink can be reduced more effectively.

In the present invention, the distance L between the guide wire opening 141 and the distal end of the base shaft 15 from the distal end is within 5 mm. When the guide wire opening 141 extends a predetermined length in the longitudinal direction of the catheter 1 as shown in the figure, the distance L is a distance from the tip of the guide wire opening 141 to the tip of the base shaft 15. Point. By doing so, the strength and strength of the catheter at this portion can be reduced without disposing another reinforcing member at the guide wire opening 141 or at a portion between the guide wire opening 141 and the distal end of the base shaft 15. The pressure resistance is sufficient, and the occurrence of kink during the procedure can be effectively prevented. In addition, the present inventors have confirmed that, when the distance L is set to 10 mm, a kink is generated with a very high probability in a portion between the guide wire opening 141 and the tip of the base shaft 15 during a procedure. .

The guide wire opening 141 does not substantially extend in the longitudinal direction, for example, by arranging the proximal end opening of the inner tube shaft 1 in a direction perpendicular to the long axis of the catheter 1. You may do so. However, as shown, by extending the guide wire opening 141 a predetermined length in the longitudinal direction of the catheter 1,
It is possible to further reduce the cross-sectional area at the guide wire opening 141 in the direction orthogonal to the long axis of the catheter 1 and to ensure a sufficient space for the guide wire to be smoothly inserted and removed from the guide wire opening 141 during the procedure. Become.

The distal end of the base shaft 15 may be located on the distal end side of the base end of the guide wire opening 141. In this case, the guide wire lumen and the base shaft are positioned with respect to the longitudinal direction of the catheter 1. 15 overlaps with the guide wire opening 141, the cross-sectional area of the guide wire opening 141 in the direction orthogonal to the long axis of the catheter 1 increases, so that the distal end of the base shaft 15 is It is preferable that the opening 141 be located closer to the base end than the base end.

Next, the materials and dimensions of each member constituting the dilatation catheter of the present invention will be described in more detail.

The base shaft 15 is preferably made of a material having relatively high rigidity, for example, a metal such as Ni-Ti, brass, SUS, or aluminum. Note that a resin such as polyimide, vinyl chloride, or polycarbonate can be used as long as the material has relatively high rigidity.

The main shaft 15 of the base shaft 15
3 has an outer diameter of about 0.3 mm to 3 mm, preferably 0.5
mm to 1.5 mm, thickness about 10 to 150 μm, preferably 20 to 100 μm, length 300 mm to 2000 m
m, preferably 700 mm to 1500 mm tube.

The base shaft entry part 1 of the base shaft 15
52 has an outer diameter of about 0.3 mm to 3 mm, preferably about 0.3 mm.
The thickness is 5 to 1.5 mm, the thickness is 10 to 150 μm, preferably 20 to 100 μm, and the length is 30 to 200 mm, preferably 50 to 180 mm.

The distal shaft 13 and the intermediate portion 14 may be constituted by the same tube, or a tube for the distal shaft and a tube for the intermediate portion may be separately prepared and connected appropriately.

In the case where the pitch of the spiral slit at the base shaft entrance is short at the distal end side as shown in the example in the figure and long at the proximal end side, the pitch is 0.1 to 10 at the distal end side.
mm, preferably 0.3 to 2 mm), and 1 to 20 mm, preferably 2 to 10 mm on the base end side. Also,
The width of the spiral slit is 1 mm or less, preferably 0.01 to
It is about 0.5 mm. Further, the tip of the spiral slit is preferably located at a position within 10 mm from the tip of the base shaft 15 to the base end side, and it is preferable that the tip of the slit reach the tip of the base shaft 15. . By locating the tip of the spiral slit in this way, even when the intermediate portion 14 is sharply bent, the portion near the tip of the base shaft 15 can be well curved, and the stress does not concentrate at one place. The occurrence of kink can be suitably reduced.

As a material constituting the tip shaft 13 and the intermediate portion 14, for example, a polyolefin (for example,
Polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more of these), cross-linked polyolefin, polyvinyl chloride, polyamide, polyamide elastomer, polyester, polyester A polymer material such as an elastomer, a polyurethane, a polyurethane elastomer, a fluororesin, a polyimide, or a mixture thereof can be used.

The tip shaft 13 and the intermediate portion 14
Outer diameter is 0.5-1.5 mm, more preferably 0.7-
The tube has a thickness of 1.1 mm, a thickness of 25 to 200 μm, more preferably 50 to 100 μm, and a length of 300 to 2000 mm, and more preferably 300 to 1500 mm.

As a material for forming the inner tube shaft 11, a material having some flexibility is used. For example, polyolefin (e.g., polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more thereof), a crosslinked polyolefin,
Polymer materials such as polyvinyl chloride, polyamide, polyamide elastomer, polyester, polyester elastomer, polyurethane, polyurethane elastomer, polyimide, and fluororesin or a mixture thereof can be used.

As shown, the guide wire opening 141
Extends a predetermined length in the longitudinal direction of the catheter 1, the length of the guide wire opening 141 in the longitudinal direction of the catheter 1 is about 0.5 to 8 mm, more preferably 2 to 8 mm.
About 5 mm.

The inner tube shaft 11 has an outer diameter of about 0.1 to
1.0 mm, preferably 0.3 to 0.7 mm, wall thickness of about 10 to 150 μm, preferably 20 to 100 μm, length of 100 to 2000 mm, preferably 200 to 1500
mm tube.

The material of the balloon 12 is preferably a material having a certain degree of plasticity so that a stenotic portion of a blood vessel can be expanded. For example, polyolefins (eg, polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, etc.), cross-linked polyolefins, polyesters (eg, polyethylene terephthalate, etc.), polyester elastomers, polyvinyl chloride , Polyurethane,
Polymer materials such as polyurethane elastomer, polyphenylene sulfide, polyamide, polyamide elastomer, and fluororesin, silicone rubber, latex rubber, and the like can be used. Also, a laminated film in which these polymer materials are appropriately laminated can be used. The balloon 12 formed by the biaxial stretch blow molding method or the like
Alternatively, the balloon 12 may be formed integrally by applying stretch blow molding or the like to the distal end portion of the distal shaft 13.

The outer diameter of the cylindrical portion of the balloon 12 when expanded is 1.0 to 10 mm, preferably 1.0 to 5.
0mm, length 5-50mm, preferably 10-40m
m, and the total length is 10 to 70 mm, preferably 1
5 to 60 mm.

The contrast marker 12 is preferably formed by a coil spring or a ring, and one or more contrast markers can be provided. As the material of the contrast marker 12, it is preferable to use a material having a high X-ray contrast property, for example, Pt, Pt alloy, W, W alloy, Au, Au alloy, Ir, Ir alloy, Ag, Ag alloy, or the like.

In the above example, the catheter has a coaxial structure in which the guide wire lumen is coaxially arranged in the distal shaft. However, the present invention is not limited to this, and the present invention is not limited to one tube (shaft). A catheter in which a guide wire lumen and a balloon inflation lumen are formed in parallel may be used.

[0042]

As described above in detail, according to the present invention, the base for preventing the kink integrated with the base shaft is formed by forming the vicinity of the tip of the base shaft by a spiral slit in a simple process such as laser processing. It is possible to provide a catheter in which a shaft penetration portion is formed and kink can be prevented from occurring in a portion having low rigidity. In addition, the distance from the distal end of the base shaft to the distal end side of the guide wire lumen that is separated from the distal end to the distal end side is within 5 mm (when the proximal opening extends over a predetermined length in the longitudinal direction of the catheter, , The distance from the tip of the base opening to the tip of the base shaft is within 5 mm), so that other reinforcements may be provided at the base opening or at a portion between the base opening and the tip of the base shaft. Even without disposing the member, the strength and pressure resistance of the catheter in this portion are sufficient, and the occurrence of kink during the procedure can be effectively prevented.

In particular, by making the pitch of the spiral slit shorter at the distal end and longer at the proximal end, the rigidity can be changed gradually over the entire shaft, and the generation of kink can be more effectively prevented.

[Brief description of the drawings]

FIG. 1 is a view showing a dilatation catheter according to one embodiment of the present invention.

FIG. 2 is an enlarged view showing main components of the dilatation catheter of FIG. 1;

FIG. 3 shows a base shaft of the dilatation catheter of FIG. 1;

FIG. 4 is a cross-sectional view showing an intermediate portion of the dilatation catheter of FIG. 1, a distal end of a base shaft, and a proximal end of the distal shaft.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Dilatation catheter 2 ... Guide wire 11 ... Inner tube shaft 111 ... Tip tip 12 ... Balloon 121 ... Contrast marker 13 ... Tip shaft 14 ... Intermediate part 141 ... Guide wire opening 15 ... Base shaft 151 ... Depth marker 152 ... Base shaft Penetration part 153: Main shaft part 16: Hub 17: Reinforcing wire

Claims (12)

[Claims] 1. A tubular base shaft having a relatively high rigidity, a tubular distal shaft provided at a distal end side of the base shaft, and having a lower rigidity than the base shaft, and between the base shaft and the distal shaft. A tubular intermediate portion that connects the base shaft and the distal shaft in a liquid-tight manner, a hub mounted near a proximal end of the base shaft, to which a pressure applying device is mounted, and a distal end of the distal shaft. A balloon, which is provided so as to be in fluid communication with the portion, and to which pressure is applied from the hub, having a distal opening on the distal side from the balloon distal end and a proximal opening on the proximal side from the balloon proximal end, A dilatation catheter having a guidewire lumen through which a guidewire is inserted, wherein a distal end of the base shaft penetrates into the intermediate portion. The penetration portion has a spiral slit, and the distance at which the base side opening of the guide wire lumen is separated from the tip of the base shaft to the tip side is within 5 mm. A dilatation catheter, characterized in that: 2. The base-side opening extends over a predetermined length in a longitudinal direction of the catheter, and a distance between a tip of the base-side opening and a tip of the base shaft is less than 5 mm. 2. The method according to claim 1, wherein
A dilatation catheter as described. 3. The dilatation catheter according to claim 1, wherein the distal end of the spiral slit is located at a position within 10 mm proximal to the distal end of the base shaft. 4. The dilatation catheter according to claim 1, wherein the base shaft is made of a metal tube. 5. The dilatation catheter according to claim 1, wherein a pitch of the spiral slit is shorter at a distal end side of the slit and longer at a proximal end side. 6. An inner tube shaft provided coaxially with the tip shaft inside the tip shaft,
The dilatation catheter according to any one of claims 1 to 5, wherein a lumen of the inner tube shaft forms the lumen for the guide wire. 7. A tube-shaped base shaft having relatively high rigidity, a tube-shaped front shaft provided at a distal end side of the base shaft and having lower rigidity than the base shaft, and between the base shaft and the distal shaft. , A tubular intermediate portion that connects the base shaft and the distal shaft in a liquid-tight manner, a hub attached near the proximal end of the base shaft, and a treatment device provided at the distal end of the distal shaft. A catheter having a distal opening on the distal side of the treatment device and a proximal opening on the proximal side of the treatment device, and a guide wire lumen through which a guide wire is inserted. The distal end of the base shaft is an intrusion that has penetrated into the intermediate portion, and the intrusion has a helical slit. Catheter distance the base side opening of the emission is separated distally from the distal end of the proximal shaft is characterized in that within 5 mm. 8. The base-side opening extends over a predetermined length in the longitudinal direction of the catheter, and the distance at which the tip of the base-side opening is separated from the tip of the base shaft toward the tip is within 5 mm. 8. The method according to claim 7, wherein
A dilatation catheter as described. 9. The dilatation catheter according to claim 7, wherein the distal end of the spiral slit is located at a position within 10 mm proximal to the distal end of the base shaft. 10. The catheter according to claim 7, wherein the base shaft is made of a metal tube. 11. The catheter according to claim 7, wherein a pitch of the helical slit is short at a distal end side of the slit and is long at a proximal end side. 12. The apparatus according to claim 1, further comprising an inner tube shaft provided coaxially with the tip shaft inside the tip shaft, wherein a lumen of the inner tube shaft forms the guide wire lumen. Claims 7 to 11
The catheter according to any one of the above.