JPH0515603A - Catheter having expanded balloon - Google Patents

Abstract

PURPOSE:To obtain a balloon catheter having high pressure resistance for PTCA.PTA and a heat resistant balloon catheter which can be used as a hot balloon catheter. CONSTITUTION:The balloon catheter is formed of polyethylene naphthalate. The polyethylene naphthalate has a high glass transition point and can be applied to the balloon catheter in which the contrast medium put therein is heated to about 80 deg.C. Since the pressure resistant strength of the balloon is high, this balloon catheter can be formed thinner than the wall thickness of the conventional balloon catheter made of PET, insofar as the strength is the same. The highly flexible balloon catheter is, therefore, obtd. and such catheter has the good passability into the bent or zigzag parts of the blood vessels, etc. Further, the formation of the thinner catheter is possible. Since the catheter has radiation resistance, the dealing with a technique used for a long-time radiation treatment is possible as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catheter having a dilatation balloon which is medically useful.

[0002]

2. Description of the Related Art A catheter equipped with an inflation balloon of this type (hereinafter referred to as a balloon catheter) is effective for many medical applications including insertion into a blood vessel or various body cavities. For example, in order to treat a stenosis in a blood vessel, the stenosis is expanded using this balloon catheter to improve blood flow on the peripheral side of the stenosis.

Conventional balloon catheters are generally formed from a thermoplastic synthetic resin material. For example, ethylene-butylene-styrene block copolymer mixed with low molecular weight polystyrene, optionally with polypropylene, and a similar composition using butadiene or isoprene in place of ethylene and butylene, poly (vinyl chloride). ), Polyurethane, polyester copolymer, thermoplastic rubber, silicone-polycarbonate copolymer,
And ethylene-vinyl acetate copolymer, or nylon-11.

Recently, polyethylene terephthalate (hereinafter referred to as PET) is used as a material, and a balloon catheter formed at a biaxial stretching temperature of 70 to 110 ° C. has also been proposed (JP-A-63-192456). ).
This PET has excellent physical properties such as toughness, flexibility and burst strength, and above all has the advantage that a balloon catheter with a thin wall can be obtained.

By the way, recently, in PTCA (percutaneous transluminal coronary angioplasty) and PTA (percutaneous transluminal angioplasty), strictures in blood vessels, especially acute coronary occlusion and restenosis are prevented. For this reason, a hot balloon catheter has been used to treat a stenosis. In this hot balloon catheter, the target chip inside the balloon and the filling liquid are heated by laser irradiation or the like to expand the narrowed portion of the blood vessel and heat-fixed for treatment, or an electrode is provided inside the balloon. A high-frequency electric field is applied between the electrode and the counter electrode on the external surface of the body to heat and fix the electrode for treatment.

[0006]

However, in the above-mentioned PTCA, the heating temperature of the contrast agent is up to about 80 ° C., but the PET balloon balloon has a glass transition point of 67 to 85 ° C. If the temperature exceeds the glass transition point of PET, the balloon catheter may be deformed, which may hinder the inflation and formation of the balloon, and it is difficult to control heating with the conventional PET balloon catheter.

Further, although the conventional PET balloon catheter has a small wall thickness, a balloon catheter having a thin wall thickness that can be inserted into a thinner blood vessel is desired.

The present invention has been made in order to solve the above-mentioned conventional problems, and can be used as a hot balloon catheter and has a thinner wall and a stronger strength than a PET balloon catheter. Another object of the present invention is to provide a balloon catheter which has high heat resistance and can withstand radiation treatment.

[0009]

The first aspect of the present invention is directed to a catheter having an inflation balloon, in which the inflation balloon and the catheter body are formed of polyethylene naphthalate.

A second aspect of the present invention has as its gist the fact that the inflation balloon is made of polyethylene naphthalate. Polyethylene naphthalate has isomers,
Polyethylene naphthalate used in the present invention (hereinafter,
The term "PEN" refers to those having a glass transition temperature (° C) several tens of degrees higher than that of PET, that is, poly (ethylene-2,6-naphthalate) and poly (ethylene-2,7-naphthalate). The glass transition temperature of the former is 113 ° C and the glass transition temperature of the latter is 119 ° C. Among them, poly (ethylene-2,6-naphthalate) has the best symmetry and has the highest melting point of 273 ° C.

The balloon of the present invention may be manufactured by using a known method for manufacturing a PET balloon. The difference is that since the glass transition point of PEN is several tens of degrees higher than that of PET, biaxial stretching is performed at this temperature or higher. That is, after a tube having a predetermined tube diameter is axially stretched within a temperature range of a glass transition point and a heat distortion temperature higher than that of PET to expand and form an inflated balloon portion to a predetermined diameter, the glass transition point temperature or less Cool to.

Further, the catheter main body may be formed by stretching a predetermined tube formed within a predetermined range within the temperature range of the heat deformation temperature and the glass transition temperature. Then, the balloon thus formed and the catheter body may be assembled by a known assembly method.

In the second aspect of the invention, the balloon of the present invention is assembled to the catheter body made of the same synthetic resin as in the conventional case.

[0014]

The PEN balloon catheter constructed as described above has a high glass transition point of PEN, so that it can sufficiently handle heating at about 80 ° C. as a hot balloon catheter. In addition, according to literature values, PEN shows that the degree of deterioration due to the elongation at break of the film after irradiation is P
Since it has about 3 times better radiation resistance than ET, it can be used for procedures used for long-term radiation therapy.

If the strength is the same as that of the PET balloon catheter, the wall thickness can be reduced. Further, since the pressure resistance is strong, it is possible to perform sufficient expansion for a high degree of stenosis.

[0016]

EXAMPLES Examples will be described below. With PEN (Teijin Ltd. product number FQ-QB, IV value 0.6), which is poly (ethylene-2,6-naphthalate), the wall thickness of the balloon portion is 6.0 μm, 8.2 μm, 10.0 μm,
13.5 μm, 16.1 μm, 20.5 μm, 24.0
Balloon catheters of μm, 26.0 μm, 27.6 μm, and 31.7 μm were manufactured by known methods.

As a comparative example, PET (manufactured by Nippon Unipet Co., Ltd., RT-580 IV value 0.6, molecular weight 20,000 to 3)
10,000), the wall thickness of the balloon part is 8.0μm, 9.0μ
m, 10.8 μm, 15.2 μm, 16.0 μm, 1
8.5 μm, 21.6 μm, 24.0 μm, 28.0 μ
m and 31.2 μm balloon catheters were manufactured by known methods.

The burst strengths of the PEN balloon catheters of the respective examples and the PET balloon catheters of the comparative examples were measured. The measurement result is shown in FIG. As can be seen from FIG. 1, the burst strength of the balloon catheter made of PEN is about twice as high as that of the balloon catheter made of PET.

Incidentally, only the balloon is formed of PEN as in the above embodiment, and the catheter body is made of PE as in the conventional case.
The above burst strength was also measured when it was formed from T, but it showed about twice as much burst strength as that of the comparative example.

Therefore, the PEN balloon catheter has a higher compressive strength than the conventional PET balloon catheter, and when the balloon catheter has the same compressive strength as the conventional one, the balloon wall thickness is the same as that of the conventional PET balloon catheter. It is possible to use a sufficiently thin one.

Therefore, the flexibility of the balloon portion is excellent,
When inserted into a bent or meandering blood vessel, etc., it can smoothly pass through those parts.

[0022]

According to the present invention, since the wall thickness can be made thin, the minimum outer diameter of the balloon catheter can be made as small as 0.4 mm, and the tube diameter of 1.5 mm or less, which was difficult in the past, can be achieved. It has become possible to insert into blood vessels.
Further, the balloon portion has excellent flexibility, and the passage of a bent or tortuous blood vessel or the like is good. Further, since the balloon portion has a high pressure resistance, it can be sufficiently expanded against severe stenosis, and it can be applied to hot balloon angioplasty which is performed to prevent restenosis. In addition, since the radiation deterioration is small, it has an excellent effect that it can be applied to a procedure used for a long-term radiation treatment.

[Brief description of drawings]

FIG. 1 is a graph showing measurement results of wall thickness and burst strength of balloons of Examples embodying the present invention.

Claims (2)

[Claims] 1. A catheter having an inflation balloon, wherein the inflation balloon and the catheter body are made of polyethylene naphthalate. 2. A catheter provided with an inflation balloon, wherein the inflation balloon is formed of polyethylene naphthalate.