JP3206064B2 - catheter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catheter, and more particularly, to a catheter with a medical balloon having a uniform shape when the balloon is expanded.

[0002]

2. Description of the Related Art As a medical balloon-equipped catheter provided with a balloon near the distal end (tip) of the catheter, for example, a catheter for indwelling in a blood vessel, a catheter for removing biliary calculi and renal ureteral calculi, etc. Various things are known.

[0003] As a catheter for indwelling in a blood vessel, for example, there is a pacing catheter with a balloon. When a disorder such as arrhythmia or heart failure occurs in the heart, a transvenous catheter electrode for extracorporeal pacemaking is inserted, and the activity of the heart is maintained by emergency pacing or temporary pacing. In this case, a pacing catheter with a balloon is usually used in accordance with the catheter method, and pacing is performed by transvenously inserting the heart into the heart.

That is, in the pacing catheter treatment method, a peripheral vein such as a femoral vein or a subclavian vein is usually punctured from an incision in the skin with a sheath introducer, and the pacing catheter is inserted into the body through the introducer. . Then, when the balloon is inflated with carbon dioxide or air, the pacing catheter is placed on the blood flow in the blood vessel and the heart, and its distal end electrode is passed through the vein, the right atrium and the tricuspid valve to the right ventricle, the target site. It can be inserted up to the apex and placed there. Since the distal end electrode of the pacing catheter is made of a hard metal such as stainless steel or platinum, the distal end electrode may cause damage to the heart and blood vessels at the time of insertion, or may cause perforation when the insertion is forcibly attempted. To prevent danger, catheters are known in which the distal end is covered with the balloon so that it does not protrude when the balloon is inflated (inflated).

[0005] Another example of a catheter for indwelling in a blood vessel is a thermodilution catheter. The Fick method, which calculates oxygen consumption and the arterial blood oxygen difference, and the indicator, which measures how much the indicator injected in the peripheral vein diminishes in the central vein, can be used to measure the heart rate, which is an indicator of the function of the heart. There is a dilution method. In the thermodilution method (thermodilution method), how much the cold water as an indicator warms is measured. When inserting a thermodilution catheter, the catheter is inserted, for example, from the left elbow vein and advanced from the subclavian vein to the superior vena cava, where the balloon at the tip is inflated and slowly advanced to allow the balloon to enter the bloodstream. Ride easily into the right ventricle and pulmonary artery. When the balloon is evacuated, the pressure of the pulmonary artery is increased, so the catheter is fixed at this site.

[0006] An example of a catheter for removing biliary and renal ureteral stones is a Fogarty catheter with a balloon. The catheter is inserted through the common bile duct incision into the common hepatic duct, and further into the intrahepatic bile duct, inflating the balloon with distilled water or saline, and slowly pulling out the catheter to remove the common bile duct stone and intrahepatic stone. Remove gall sand. When performing intrabiliary imaging, with the balloon inflated, through the lumen communicating with the distal end of the catheter,
An injection of a contrast agent is performed. For this reason, it is preferable that the balloon has a large outer diameter and is uniformly expanded.

[0007] The balloon provided in these catheters is made of a film (membrane) formed of an elastic material and desirably has excellent pressure sensitivity, mechanical properties, and antithrombotic properties. Examples of the material of the elastic material include silicon rubber, polyurethane, and natural rubber. In order to manufacture a balloon using these elastic materials, a dipping method of forming a film by immersing a mold in an organic solvent solution of the elastic material is usually employed.

As shown in FIG. 3, the balloon catheter (3) usually has a balloon (2) attached near a distal end (1) which is a tip thereof. Depending on the application of the catheter, the distal end (1) is provided with a pointed hole, an electrode or a thermistor or the like. In some cases, when the balloon (2) is expanded, it covers the distal end (1) and prevents its protrusion.

[0009] However, conventional balloons often do not expand uniformly and tend to be uneven in shape. Specifically, as shown in FIG. 2, the center position of the expanded balloon (2) is shifted and eccentric with respect to the distal end (1).

When the expanded balloon shape is biased,
For example, in the case of an intravascular indwelling catheter, it is difficult for the balloon to cover the distal end, and there is a risk that the hard metal distal end electrode may damage the heart and the inner wall of the blood vessel. In addition, there is a risk that arrhythmia may occur due to stimulation of the inner wall of the heart by the distal end. Regarding the catheter for removing biliary calculus and renal ureteral calculus, if the balloon shape is uneven and nonuniform, it is difficult to sufficiently remove the calculus and the like. Also, the operation of injecting a contrast agent into the bile duct becomes difficult.

However, conventionally, sufficient attention has not been paid to such a bias of the balloon shape, and no effective method for preventing the bias has been proposed.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide a medical balloon-equipped catheter which is excellent in functionality without unevenness in the shape of the balloon when inflated. The present inventors have conducted research on the cause of the occurrence of bias in the balloon shape of the catheter.As a result, the conventional balloon material has a relatively large elongation at break, which causes the balloon shape to be biased when the balloon is inflated. Was found.

That is, the present inventors made balloons having different sleeve diameters, wall thicknesses, swelling degrees, elongation at break, etc. using various elastic materials, and examined the causes of the bias of the balloon shape. It has been found that a balloon made of a film (membrane) with low elongation shows an unbiased shape when expanded.

Heretofore, in order to make the balloon easy to inflate and expand to a large shape, the balloon has been formed of a film having a relatively large breaking elongation. At the time of treatment, the balloon is inflated by a certain amount of insufflation.In this case, the balloon is not fully inflated. Deviation occurs. In addition, the larger the breaking elongation, the larger the balloon outer diameter is likely to be due to a certain amount of air supply. These can be presumed to be the causes of the deviation of the balloon outer diameter during expansion.

[0015] In contrast to this, to prepare the balloon of an elastic material that provides a small film of elongation at break, was subjected to balloon shape evaluation at the time of expansion, an elongation at break of 700 to 800
% Of the film was found to swell uniformly under normal use conditions, and the deviation of the balloon shape was remarkably improved. The present invention has been completed based on these findings.

[0016]

Thus, according to the present invention, in a catheter with a medical balloon, the balloon is made of natural rubber, polyurethane and silicone rubber.
A catheter formed of at least one elastic material selected from the group consisting of a film having a breaking elongation of 700 to 800% .

Hereinafter, the present invention will be described in detail. In the catheter with a balloon of the present invention, the material forming the balloon is preferably an elastic body and has excellent pressure sensitivity, mechanical properties, and antithrombotic properties. As such an elastic material, for example, various elastic materials known as balloon materials such as silicone rubber, polyurethane, and natural rubber can be suitably used. The polyurethane includes not only polyurethane but also polyurethane polymers such as polyurethane urea, polyurethane / silicone block copolymer, fluorinated polyurethane, and fluorinated polyurethane urea. Further, a blend of polyurethane and a different polymer may be used, such as a blend of polyurethane and polydimethylsiloxane.

In order to produce a balloon using an elastic material, various film forming methods can be adopted, but a dipping molding method is generally preferred. In the dipping molding method, an elastic material and, if necessary, various additives are dissolved in an organic solvent to form a solution, and a mold is immersed in the solution to form a film. The solution is applied to the surface of the mold by immersing the mold in the solution, and the solvent is evaporated to form a film on the surface of the mold. By repeating immersion and drying, a film (film) having a desired thickness can be formed by lamination. Depending on the type of the elastic material, it is vulcanized or crosslinked after film formation.

The elastic material film forming the balloon of the present invention must have an elongation at break of 800% or less.
You . When the elongation at break exceeds 800 %, the outer diameter of the manufactured balloon becomes relatively large by a certain amount of air supply, but the shape tends to be uneven. The lower limit of the breaking elongation is that the balloon can cover the catheter distal end at the time of inflation, that the balloon shape required at the time of inflation can be secured, and that the balloon is difficult to break, etc. It needs to be up to 700% . Therefore, the range of the elongation at break of the balloon material in the present invention is 700 to 800%.

In the present invention, the value of elongation at break is determined according to JIS.
According to K-6301, a tensile tester (TOYO
BALDWIN Co. (Manufactured by LTD.) Under the conditions of a crosshead speed of 500 mm / min, a temperature of 23 ° C., and a humidity of 65%.

The balloon material in the catheter of the present invention preferably has a bias occurrence rate of 10 or less and a balloon breakage rate of 10% or less as measured by a measurement method described later.

In order to reduce the elongation at break of a film formed of an elastic material to 850% or less, for example, when natural rubber is used, the type and amount of a vulcanizing agent or vulcanization accelerator are changed. There is a method of appropriately selecting the compounding formulation, and in the case of polyurethane, a method of adjusting the constituent components and molecular weight, and the like, and is not particularly limited.

[0023]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples, but the present invention is not limited to only these Examples. In addition, the measuring method of physical properties is as follows.

<Evaluation Elongation> Determined by a tensile tester. The measurement conditions were measured and calculated according to the following method in accordance with JIS K-6301. Tensile tester: TOYO BALDWIN Co. LTD
Temperature: 23 ° C Humidity: 65% Crosshead speed: 500 mm / min

<Declination Occurrence Rate> A predetermined amount of air (0.8 cc) was injected into a balloon attached to a catheter tube, and a laser outer diameter measuring device (LS-31, manufactured by Keyence Corporation) was used.
00), the balloon shape was measured. The maximum value of the measured balloon outer diameter was defined as the balloon outer diameter.

As shown in FIGS. 1 and 2, the outer diameter of the balloon is divided into lengths a and b from the center line of the distal end of the catheter.
The ratio was defined as the degree of bias, and the degree of bias was determined to be 1.8 or more in terms of the presence or absence of appearance and appearance of the catheter distal end. Then, the rate of occurrence of bias in each sample is
It was expressed as the bias occurrence rate. The number of samples was 100 each.

<Balloon Breakage Rate> Three times the specified amount of air was injected into a balloon attached to a catheter tube, which was a test sample, and the proportion of the balloon broken at that time was measured. The reason for adopting this test method is that when the balloon is expanded, the balloon part is located inside the body, so it may not be possible to clearly confirm the presence or absence of expansion. This is because there is a risk of injecting carbon dioxide gas or air again. It is desirable to use a balloon which is hardly damaged even when gas is injected twice, preferably three times the specified amount.

Examples 1-3, Comparative Examples 1-2 Potassium hydroxide solution, potassium laurate solution, sulfur dispersion as a vulcanizing agent, zinc oxide dispersion, and vulcanization accelerator were added to natural rubber latex. Formulated with a zinc dibutyldithiocarbamate dispersion, prepared by changing the vulcanization accelerator to tetramethylthiuram disulfide, dibenzothiazyl disulfide, diphenyl guanidine, etc., and varying the elongation at break. Using each of them as an elastic material, a film was formed by a dipping molding method, and then vulcanized to produce a natural rubber balloon material (film) having a thickness of 0.2 mm.

The elongation at break of each balloon material thus obtained was measured. Next, each balloon material cut to a length of 6.0 mm was attached to a distal end portion of a polyurethane catheter tube having an outer diameter of 1.6 mm by a known method, and a balloon portion and a pacing catheter tip portion were attached. Was prepared. The number of fabricated samples was 100 each, and the rate of occurrence of bias and the rate of balloon breakage were measured. Table 1 shows the results
Shown in

[0030]

[Table 1]

As is apparent from Table 1, when a conventional balloon material having a large breaking elongation was used (Comparative Example 1),
Extremely high bias generation rate. On the other hand, when the breaking elongation of the balloon material is 700 to 800% (Examples 1 to 3)
It can be seen that the deviation of the balloon shape during expansion is significantly reduced. In addition , from the viewpoint of balloon breakage rate (Comparative Example
2) The elongation at break must be 700% or more
You .

[0032]

According to the present invention, there is provided a catheter with a balloon in which the bias in the shape of the balloon is remarkably prevented and the balloon is excellent in functionality. The catheter of the present invention, since the balloon portion can exhibit its function without any problem,
It is suitable as various balloon catheters.

[Brief description of the drawings]

FIG. 1 is a front view showing an unbiased balloon shape after expansion.

FIG. 2 is a front view showing a biased balloon shape after expansion.

FIG. 3 is a schematic view of a catheter with a balloon.

[Explanation of symbols]

Reference Signs List 1 catheter distal end 2 balloon 3 balloon catheter a length of longest part from catheter centerline to balloon outer diameter b length of shortest part from catheter centerline to balloon outer diameter

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-206452 (JP, A) JP-A-4-144572 (JP, A) JP-A-5-35148 (JP, U) 24074 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61L 29/00-29/18 A61M 25/10-25/12

Claims (1)

(57) [Claims] 1. A catheter with a medical balloon, wherein the balloon is made of natural rubber, polyurethane or silicone.
A catheter comprising a film having a breaking elongation of 700 to 800% and formed of at least one elastic material selected from the group consisting of rubber .