JP2001314512A - Balloon having uniform film thickness and balloon catheter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a balloon and a balloon catheter capable of being thinned while having sufficient pressure-proof strength and also having flexibility for facilitating insertion into a bending stricture part and a manufacturing method of the balloon. SOLUTION: This balloon for medical use has the ratio of a straight tube part film thickness standard deviation to a straight tube part film thickness average value of not more than 0.090. The balloon catheter is constituted by using the balloon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a balloon catheter, and more particularly, to dilatation treatment of a vascular stenosis in percutaneous luminal surgery including peripheral vascular shaping, coronary vascular shaping and valvular shaping, and to the peripheral side. The present invention relates to a balloon catheter used for improving blood flow.

[0002]

2. Description of the Related Art Conventionally, when stenosis or occlusion occurs in a blood vessel such as a blood vessel, angioplasty is performed to improve the blood flow on the peripheral side of the blood vessel by expanding the stenotic part or the occluded part of the blood vessel. (PTA: Percutaneous Transluminal An
gioplasty, PTCA: Percutaneous Transluminal Cor
Onary angioplasty) has been used in many medical institutions and has become a common surgical procedure in such cases.

[0003] A balloon catheter is mainly used as a set of a guide catheter and a guide wire in order to dilate a stenosis site of a coronary artery. In angioplasty using this balloon catheter, a guide catheter is first inserted from the femoral artery, the distal end is positioned at the entrance of the coronary artery via the aorta, and then a guide wire passed through the balloon catheter is used to narrow the coronary artery. Advanced over the site, then advance the balloon catheter over the guidewire, inflate the balloon at the site of the stenosis, expand the stenosis, and deflate the balloon to remove it from the body You do it. However, balloon catheters are useful not only for treating arterial stenosis, but for many medical applications, including insertion into blood vessels, as well as into various body cavities.

[0004] The balloon provided at the distal portion of the catheter shaft is required to have various characteristics due to its role of expanding a stenosis in a blood vessel. High compressive strength is required to expand a calcified hard stenosis. In addition, high flexibility is required to be positioned at a bent stenosis site. In addition, in order to locate a stenosis site having a very high stenosis degree such as 99% stenosis degree, not only flexibility but also a sufficiently thin balloon is required. Taken together, these characteristics require that the balloon be thin, have high membrane strength, and have high flexibility.

[0005] A number of methods have heretofore been disclosed for making the balloon thinner and stronger. For example, Tokuhei 3
JP-A-37949 discloses a balloon made of polyethylene terephthalate (PET). This balloon realizes a thin wall, high strength, and has excellent dimensional stability. However, disadvantages include lack of flexibility and pinhole destruction. In particular, pinhole destruction is not preferable because when a balloon is broken in a blood vessel, a high stress is locally applied to the blood vessel wall, and the risk of causing damage to the blood vessel wall is extremely high.

Japanese Patent No. 2555298 discloses a balloon for a catheter in which the ratio of the thickness of the straight pipe portion to the thickness of the tapered portion is 1.2 or less. In this method, flexibility and high strength can be realized, but since the tapered portion is stretched again after the balloon is formed, the tapered portion is thinned.
In reality, it is difficult to stretch only the tapered portion, and the film is stretched to the straight pipe portion. Therefore, it is extremely difficult to control the film thickness of the entire balloon, and there is a problem that the balloon forming yield is reduced. Further, since the balloon has to be biaxially stretched again after being stretched again, there is a problem that the molding cycle becomes longer.

As is evident from the above examples, the methods disclosed so far have provided balloons with excellent properties, but on the other hand, are not perfect methods because they cause other problems.

[0008]

SUMMARY OF THE INVENTION In view of the above situation, the present invention is intended to solve the problem by making it possible to reduce the thickness while maintaining sufficient pressure resistance, and to insert it into a bent stenosis site. Another object of the present invention is to easily provide a balloon having flexibility for facilitation.

[0009]

As a result of intensive studies to solve the above problems, it has been found that the ratio of the standard deviation of the thickness of the straight pipe portion to the average value of the straight pipe portion film thickness of a medical balloon is as follows. The inventors have invented a balloon having a diameter of 0.090 or less.

A balloon catheter provided with a collapsible balloon used for medical treatment for the purpose of dilatation operation, wherein the ratio of the standard deviation of the straight tube portion film thickness to the average straight tube portion film thickness value of the balloon is provided. A balloon catheter with a balloon of 0.090 or less was constructed.

The balloon is formed by extrusion molding, the variation of the outer diameter is within a range of an average outer diameter value ± 0.013 mm, and the ratio of the maximum thickness to the minimum thickness on the cross section is 1.08 or less. Is manufactured by biaxial stretch blow molding of parison.

In order for the balloon to have sufficient pressure resistance, a certain thickness is required. On the other hand, it is desirable that the film thickness be small in order to have flexibility. The actual straight film thickness of the balloon is not constant everywhere but varies. If the average film thickness at the balloon straight tube is the same,
The larger the variation, the lower the pressure resistance. This is because a large variation means that there is a portion much thinner than the average value, and when pressure is applied to the balloon, stress concentrates on the thin portion and rupture occurs from that portion. That is, by reducing the variation in the film thickness of the straight tube portion of the balloon, the thickness can be reduced while maintaining sufficient pressure resistance, and flexibility can be imparted.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a balloon, characterized in that the ratio of the standard deviation of the straight tube portion film thickness to the average value of the straight tube portion film thickness is 0.090 or less. This is a method for manufacturing a balloon.

The thermoplastic resin used as a raw material of the balloon of the present invention includes polyolefin, polyamide, polyurethane, polyester, polyolefin elastomer,
Although any thermoplastic resin such as polyamide-based elastomer, polyurethane-based elastomer, and polyester-based elastomer can be used, polyamide-based elastomer is most preferable because it has high pressure resistance and has some flexibility.

In the present invention, the ratio of the film thickness standard deviation to the film thickness average value is measured and calculated by the following method.

The balloon is inflated by applying a pressure of 6 atm, and is inflated along the longitudinal direction of the balloon (see the arrow in FIG. 1).
The film thickness of the straight pipe portion is measured at a measurement spot diameter of 2 μm every 1 mm. From the obtained data, the ratio of the standard deviation of the film thickness to the average value is calculated according to Equation 1.

[0017]

(Equation 1) The apparatus for measuring the film thickness is not particularly limited, but a laser confocal displacement meter (LT801 manufactured by Keyence Corporation)
If 0) is used, the measurement of the measurement spot of 2 μm can be performed without contacting the measurement section.

The balloon of the present invention is manufactured by extrusion molding in which the outer diameter fluctuation is within the range of the average outer diameter value ± 0.013 mm and the ratio of the maximum thickness to the minimum thickness on the cross section is 1.08 or less. The molded parison is subjected to biaxial stretch blow molding.

In order to form a parison having high dimensional accuracy, a resin pressure control mechanism for adjusting the screw rotation speed so as to keep the resin pressure at a set value, and an external mechanism for adjusting the take-off speed so as to keep the parison outer diameter at a constant value. It can be realized by using a diameter control mechanism and an ultrasonic online thickness measuring device for measuring the thickness of the parison during extrusion.

In order to obtain the balloon of the present invention, it is desirable that there is no foreign substance in the parison, and in order to produce such a parison, it is desirable to use a filter during extrusion molding.

FIG. 1 is a schematic sectional view showing one embodiment of a balloon of the present invention, and FIG. 2 is a schematic sectional view showing one embodiment of a balloon catheter of the present invention.

The balloon 1 of the present invention has a straight pipe portion 2 which expands or contracts by the introduction of a pressurized fluid, a proximal taper portion 3a which is connected to both ends of the straight pipe portion 2 and has a diameter decreasing toward the outside. And a proximal sleeve portion 4 on a cylinder connected to the tapered portions 3a and 3b.
a and the distal sleeve portion 4b.

In the balloon catheter of the present invention, as shown in FIG. 2, a catheter shaft for joining the balloon has at least a distal portion, an inner tube 5 having an open distal end and a first lumen 5L, and a distal end. Is located closer to the distal end of the inner tube than the inner tube, is arranged substantially coaxially with the inner tube, and has an outer tube 6 having a second lumen 6L between the inner tube and the inner tube. If there is, the kind of material constituting the inner tube 5 and the outer tube 6 is not particularly limited. That is, existing materials such as polyolefin, polyamide, polyester, polyurethane, polyimide, polyolefin elastomer, polyamide elastomer, polyester elastomer, and polyurethane elastomer can be used.
The combination of the material types of the outer tube 6 and the outer tube 6 is not particularly limited, and a material having physical properties according to the purpose of use can be selected.

The method of joining the balloon 7 with the inner tube 5 and the outer tube 6 is not particularly limited.
It goes without saying that a known method such as adhesion with an adhesive can be adopted. In addition, one or more radiopaque markers 9 can be applied to the inner tube 5 existing inside the balloon 7 without limiting the effects of the present invention.

[0025]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but these do not limit the present invention in any way.

(Example 1) As an inner tube, a high-density polyethylene HY540 (manufactured by Mitsubishi Chemical Corporation) was extruded to an inner diameter of 0.42.
mm and a tube having an outer diameter of 0.56 mm. Also,
Polyamide elastomer PEBAX6333 as outer tube
SA00 (manufactured by Elf Atochem) was formed into a tube having an inner diameter of 0.71 mm and an outer diameter of 0.90 mm by extrusion. The inner tube and the outer tube were arranged in a coaxial double tube to form a catheter shaft.

Polyamide elastomer PEBAX70
Using a Davis Standard extruder equipped with a resin pressure control mechanism and an outer diameter control mechanism, the thickness of the 33SA01 (manufactured by Elf Atochem) was measured at four points on the parison cross section using an ultrasonic online thickness measuring device. After adjusting the center of the die while adjusting the screw speed so that the resin pressure is equal to the set value, the take-up speed is adjusted so that the outer diameter is equal to the set value. A parison having a diameter of 0.41 mm and an outer diameter of 1.02 mm was formed. Table 1 shows the parison outer diameter fluctuation value and the ratio of the maximum thickness to the minimum thickness.

The parison was biaxially stretch blow-molded to form a catheter balloon having an outer diameter of 3.0 mm.

The balloon is attached to the catheter shaft by a two-part curable urethane adhesive UR0531 (HBF).
(made by ULLER Co., Ltd.), and the balloon portion was wrapped and sterilized by EOG to obtain a balloon catheter sample.

The balloon is inflated by applying a nitrogen pressure of 6 atm and a laser confocal displacement meter L manufactured by Keyence Corporation.
0.1 mm along the longitudinal direction of the straight pipe part by T-8010
Table 1 shows the results obtained by measuring the film thickness for each sample and calculating the ratio of the standard deviation of the film thickness to the average value according to Equation 1.

The balloon catheter sample was heated at 37 ° C.
Table 1 shows the results of measurement of the resistance value when inserted into a U-shaped simulated bent stenosis vessel plate (see FIG. 3) placed in a physiological saline solution and passed through a stenosis portion.

As shown in FIG. 3, the U-shaped simulated bent stenosis vessel plate has a U-shaped groove formed on the surface of the acrylic plate 10 and has an inner diameter of 3.00 mm along the U-shaped groove. A simulated bent blood vessel is provided by disposing a polyethylene tube 11, and the bent portion of the U-shaped simulated bent blood vessel forms a semicircle having a diameter of 150 mm in inner diameter. The inside diameter is 0.95 mm and the outside diameter is 2.9 at the bent portion of the U-shaped simulated blood vessel.
An 8 mm polyethylene tube 12 was fixed coaxially to obtain a simulated bent stenosis blood vessel. The balloon catheter sample was connected to a force gauge 14 using a clamp 15, and a force gauge 1 was connected using a slide table 13.
4 was advanced at a speed of 10 mm / sec, and the maximum resistance value when passing through the simulated bending stenosis blood vessel was measured. The measurement is n =
3 and the measured values in Table 3 are the average values. At the time of the measurement, the guide wire 16 was inserted in advance from the first lumen 5L inside the inner tube 5 into the simulated bent stenosis blood vessel.

A sample other than the balloon catheter sample whose resistance was measured was placed in a water tank filled with physiological saline at 37 ° C., and 0.2 at
The pressure was increased by m. Each pressure was maintained for 1 second, and the pressure was continuously increased until the balloon was broken. The results of measuring the burst pressure of the balloon are shown in Table 1. The measured value is an average value of n = 3.

(Comparative Example 1) The extruder used in Example 1
Without controlling the resin pressure and outer diameter, the die was centered while measuring the thickness of four points on the parison cross section using an ultrasonic online thickness measuring device, and the set temperature was set at 22.
At 0 ° C., a parison having an inner diameter of 0.41 mm and an outer diameter of 1.02 mm was formed. Table 1 shows the variation value of the outer diameter and the value of the ratio of the maximum thickness to the minimum thickness.

A catheter balloon having an outer diameter of 3.0 mm was formed from the parison in the same manner as in Example 1. Also,
Using the same shaft as in Example 1, a balloon catheter was prepared from the balloon in the same manner as in Example 1.

Table 1 shows the results of measurement of the resistance value and the breakdown pressure when passing through the constriction by the same method as in Example 1.

Table 1 shows the results obtained by measuring the film thickness of the straight tube portion of the balloon in the same manner as in Example 1 and calculating the ratio of the standard deviation to the average value.

(Comparative Example 2) The extruder used in Example 1
The center of the die is adjusted without using the ultrasonic online thickness measuring device, the screw speed is adjusted so that the resin pressure is equal to the set value, and the take-up speed is adjusted so that the outer diameter is equal to the set value. At a set temperature of 220 ° C, the inner diameter is
A parison having a diameter of 41 mm and an outer diameter of 1.02 mm was formed. Table 1 shows the variation in the outer diameter of the parison and the ratio of the maximum thickness to the minimum thickness.

A catheter balloon having an outer diameter of 3.0 mm was formed from the parison in the same manner as in Example 1. Also,
Using the same shaft as in Example 1, a balloon catheter was prepared from the balloon in the same manner as in Example 1.

Table 1 shows the results of measurement of the resistance value and the breakdown pressure when passing through the constriction by the same method as in Example 1.

Table 1 shows the results of measuring the film thickness of the straight tube portion of the balloon in the same manner as in Example 1 and calculating the ratio of the standard deviation to the average value.

[0042]

[Table 1] In the first embodiment, the extruder equipped with a resin pressure control mechanism, an outer diameter control mechanism, and an ultrasonic online thickness measuring device is used to control the resin pressure and the outer diameter, and perform parison extrusion while measuring the thickness. As a result, a parison having a small parison outer diameter fluctuation width and a small ratio of the parison wall thickness maximum value to the minimum value was obtained,
As a result, a balloon having a small ratio of the film thickness standard deviation to the average value is obtained, and as a result, the balloon has both a high average burst pressure and flexibility to pass through a flexion constriction.

In Comparative Example 1, the parison was extruded by using an ultrasonic online thickness measuring apparatus without controlling the resin pressure and the outer diameter during the parison extrusion. as a result,
Although the value of the ratio of the maximum parison thickness to the minimum thickness became smaller, the fluctuation range of the outer diameter became larger, and as a result, the ratio of the balloon thickness standard deviation to the average value became larger. As a result, it is considered that although the flexibility to pass through the bent portion was obtained, the average breaking pressure was reduced.

In Comparative Example 2, parison extrusion was performed using a resin pressure control and outer diameter control mechanism without using an ultrasonic online thickness measuring apparatus. As a result, the outer diameter fluctuation width of the parison is reduced, but the ratio of the maximum thickness of the parison to the minimum thickness is increased. As a result, it is considered that the ratio of the standard deviation of the film thickness of the balloon to the average value was increased, and as a result, the flexibility to pass through the bent portion was obtained, but the average breaking pressure was reduced.

[0045]

As described above, the balloon according to the present invention and the balloon catheter having the balloon joined thereto are:
By reducing the variation in the film thickness of the straight tube portion of the balloon, it is possible to simultaneously achieve high pressure resistance and thinness and flexibility of the balloon portion, and as a result, to improve the permeability of the balloon portion to the bending stenosis. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a balloon of the present invention.

FIG. 2 is an enlarged partial cross-sectional view showing a bonding portion between a balloon and a catheter shaft according to the present invention.

FIG. 3 is a simplified diagram showing a U-shaped simulated bent stenosis vessel plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Balloon 2 Straight tube part 3a Proximal taper part 3b Distal taper part 4a Proximal sleeve part 4b Distal sleeve part 5 Inner tube 5L 1st lumen 6 Outer tube 6L 2nd lumen 7 Balloon 8 Joining Part 9 X-ray opaque marker 10 Acrylic plate 11 Polyethylene tube (simulated bent blood vessel) 12 Polyethylene tube (simulated bent blood vessel stenosis) 13 Slide table 14 Force gauge 15 Clamp 16 Guide wire

Claims (5)

[Claims] 1. A medical balloon, wherein the ratio of the standard deviation of the straight tube portion film thickness to the average straight tube portion film thickness value of the balloon is 0.
090 or less balloon. 2. A balloon catheter having a foldable balloon used for medical treatment for expanding operation, wherein the balloon catheter has the balloon according to claim 1. 3. A parison for producing a medical balloon, wherein the outer diameter varies within a range of an average outer diameter ± 0.013 mm, and a ratio of a maximum thickness to a minimum thickness on a cross section. Is less than or equal to 1.08. 4. A method of making a parison for making a medical balloon, comprising: (1) at least three parisons on a parison cross section;
Measuring the wall thickness at a point, (2) aligning the center of the die, (3) adjusting the screw rotation speed so that the resin pressure matches the set value, and (4) adjusting the outer diameter to the set value. 4. The method for producing a parison according to claim 3, further comprising a step of adjusting the take-off speed so as to match. 5. The method for producing a medical balloon according to claim 1, wherein the parison according to claim 3 is subjected to biaxial stretching blow molding.