JPH05220215A - Catheter - Google Patents

Abstract

PURPOSE:To provide a medical catheter with a balloon having very little bias in the balloon shape when expanded, very little slack generated when shrunk, and excellent functional property. CONSTITUTION:In a medical catheter with a balloon, the balloon is formed with a film made of an elastic material and having the 500%-modulus within the range of 28-50kg/cm<2>.

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 which has a very small shape deviation when the balloon is expanded and has a very small slack when the balloon is deflated.

[0002]

2. Description of the Related Art As a catheter with a medical balloon having 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 stones / nephroureteral stones, etc. Various things are known. An example of a catheter for indwelling in a blood vessel 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 normal cardiac activity is maintained by emergency pacing or temporary pacing. In this case, usually, a pacing catheter with a balloon is used in accordance with the catheter method, and the pacing is performed by transvenous insertion into the heart.

That is, in the method of applying a pacing catheter, usually, a peripheral vein, for example, a femoral vein or a subclavian vein is punctured through a skin incision portion with a sheath introducer, and the pacing catheter is inserted into the body through this introducer. .. The balloon is then inflated with carbon dioxide or air, and 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, right atrium and tricuspid valve to the target site, the right ventricle. It can be inserted 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, it causes damage to the heart and blood vessels due to the distal end electrode during insertion, or may cause perforation when forced to insert. In order to prevent a risk, there is also known a catheter in which the distal end portion is covered with the balloon and does not protrude when the balloon is expanded (inflated).

Another example of a catheter for indwelling in a blood vessel is a thermodilution catheter. The Fick method, which is calculated from the oxygen consumption and the arterial oxygen difference, and the indicator method, which measures how much the indicator injected by peripheral vein infusion dilutes in the central vein, are used to measure the heart rate, which is an indicator of the functioning of the heart. There is a dilution method. The thermodilution method (thermodilution method) measures how much cold water, which is an indicator, warms up. When inserting a thermodilution catheter, insert the catheter, for example, from the left elbow vein and advance it from the subclavian vein to the superior vena cava, inflate the balloon at the tip here, and slowly advance the balloon to the bloodstream. It gets on and is easily inserted into the right ventricle and pulmonary artery. Since the pressure in the pulmonary artery is increased when the gas in the balloon is removed, the catheter is fixed at this site.

An example of a catheter for removing biliary calculi / nephroureteral stones is a Fogerty 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, and the balloon is inflated with distilled water or saline solution, and the catheter is slowly pulled out, to determine the common bile duct stones and intrahepatic stones, Remove gall and sand. When performing cholangiography, with the balloon inflated, through the lumen communicating with the distal end hole of the catheter,
Injection of contrast agent is performed. Therefore, it is preferable that the outer diameter of the balloon is large and that the balloon be uniformly expanded.

The balloons provided in these catheters are made of a film made of an elastic material, and it is desirable that they have excellent pressure sensitivity, mechanical properties and antithrombotic properties. Examples of the material of the elastic material include silicone rubber, polyurethane and natural rubber. In order to manufacture a balloon using these elastic materials, a dipping method in which a mold is immersed in an organic solvent solution of the elastic material to form a film is usually employed.

As shown in FIG. 3, the balloon catheter (3) usually has a balloon (2) attached in the vicinity of the distal end (1) which is the apex thereof. Depending on the intended use of the catheter, the distal end (1) is provided with a pointed hole, electrode or thermistor or the like. Balloon (2)
When expanded, some cover the distal end (1) to prevent its protrusion.

However, conventional balloons often do not expand uniformly, and the shape is apt to be uneven. Specifically, as shown in FIG. 2, the center position of the expanded balloon (2) deviates from the distal end (1) and is eccentric. In addition, the conventional balloon is liable to cause slack when the balloon is deflated, and therefore, a thrombus is likely to be generated in the slack portion.

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 portion, and the distal end electrode made of hard metal may damage the heart and the inner wall of the blood vessel. There is also a risk of arrhythmia due to stimulation of the inner wall of the heart by the distal end. Regarding a catheter for removing biliary stones / nephroureteral stones, if the balloon shape is uneven and uneven, it becomes difficult to sufficiently remove the stones and the like. Also, the operation of injecting a contrast agent into the bile duct becomes difficult. However, in the past, sufficient attention has not been paid to such uneven balloon shape, and no effective method has been proposed to prevent such unevenness.

[0010]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a catheter with a balloon for medical use, which has an extremely small deviation in the shape of the balloon when inflated and an extremely small amount of slack when deflated, and which has excellent functionality. To do.
The present inventors have conducted a study on the cause of the occurrence of bias in the balloon shape of the catheter, and the cause of the occurrence of slack, the conventional balloon has a relatively small tensile stress, when it is inflated, It has been found that this is a cause of giving a bias to the balloon shape and causing slack.

That is, the present inventors have prepared balloons having various sleeve diameters, wall thicknesses, swelling degrees, tensile stresses, etc. using various elastic materials, and examined the cause of the balloon shape deviation. It has been found that a balloon made of a film with a high stress (500% modulus) exhibits an unbiased shape when expanded. It has also been found that an elastic material having a permanent set of 20% or less is preferable in order to form a balloon having little slack.

Conventionally, in order to make a balloon inflatable and to expand it into a large shape, the balloon is formed of a film having a relatively low tensile stress. At the time of measures, the balloon is inflated by a fixed amount of air supply, but in that case, it is not fully inflated, so to speak, it is used during the stage of expansion, so in the case of conventional balloons with low tensile stress,
It is not uniformly expanded and is apt to be biased, and contraction is likely to cause slack. In addition, the lower the tensile stress, the larger the outer diameter of the balloon tends to be due to the supply of a fixed amount of air. These are
It can be presumed that this is the cause of the uneven outer diameter of the balloon during expansion.

On the other hand, when a balloon was made from an elastic material which gives a film having high tensile stress and the shape of the balloon when expanded was evaluated, the 500% modulus was 28 kg.
It has been found that a balloon made of a film having a thickness of at least 1 cm ² / cm ² bulges uniformly under normal use conditions and the deviation of the balloon shape is remarkably improved. Further, it was also found that the occurrence of slack is extremely low by using an elastic material having a permanent set of 20% or less. The present invention has been completed based on these findings.

[0014]

Thus, according to the present invention, in a catheter with a medical balloon, a 500% modulus in which the balloon is made of an elastic material is 28 to 50%.
There is provided a catheter characterized by comprising a film of 50 kg / cm ² .

The present invention will be described in detail below. In the catheter with a balloon of the present invention, the material forming the balloon is preferably an elastic body and is excellent in pressure sensitivity, mechanical properties and antithrombotic property. As such an elastic material, for example, various elastic materials known as balloon materials such as silicone rubber, polyurethane and natural rubber can be preferably used.

The polyurethane includes not only polyurethane but also polyurethane-based polymers such as polyurethane urea, polyurethane / silicone block copolymer, fluorinated polyurethane and fluorinated polyurethane urea. It also includes blends of polyurethanes with dissimilar polymers, such as blends of polyurethanes with polydimethylsiloxane. Among them, crosslinked polyurethane is preferable for forming a balloon having a permanent set of 20% or less.

Examples of polyurethane polymers include 4,4'-diphenylmethane diisocyanate (M
DI), hydrogenated MDI, diisocyanate such as hexamethylene diisocyanate, and urethane or urea bond composed of 1.4-butanediol and short-chain diol such as ethylene glycol as a hard segment, and polyoxytetramethylene glycol, polyoxypropylene glycol, etc. Polyurethanes, adipic acid esters such as ethylene adipate and butylene adipate, and polyurethanes having a soft segment such as aliphatic polyesters such as polycaprolactone and polycarbonate. As the chain extender, a short chain diol such as 1.4-butanediol or ethylene glycol, or a diamine such as ethylenediamine is used.

The polyurethane polymer can be synthesized by a prepolymer method, a one shot method, or other method. Crosslinking of polyurethane-based polymers includes various crosslinks such as allophanate crosslinks and buret crosslinks.
In the present invention, when the polyurethane-based polymer is cross-linked, it is formed into a predetermined shape and then cross-linked.

To form a polyurethane polymer film into a predetermined shape and then crosslink it, for example, there is a method of using an incomplete polyurethane in which active isocyanate groups remain at the ends of the molecular chain or in the molecular chain. The incomplete polyurethane can be obtained by charging diisocyanate forming a hard segment of polyurethane in a stoichiometric excess with respect to the polyol compound and polymerizing. When a film is formed into a predetermined balloon shape using this incomplete polyurethane and then heated, allophanate crosslinking occurs due to residual isocyanate groups. The heat treatment for crosslinking is usually 80 to 1
It is carried out by heating at 50 ° C. for several tens of minutes to several hours.

There is also a method of using a polyurethane to which a curing agent, an organic peroxide and the like have been added, and after film formation, heating to crosslink. In the case of moisture-curable polyurethane, it can be crosslinked by leaving it in the air after film formation.

As another cross-linking method, a cross-linking method using a monomolecular polyisocyanate can be mentioned. After forming a polyurethane polymer film into a predetermined shape, it is immersed in a solvent containing polyisocyanate, and then heated to crosslink. For example, in a tetrahydrofuran solution in which 4,4'-diphenylmethane diisocyanate is dissolved, a film formed into a predetermined shape is immersed for several seconds to several tens seconds,
After pulling up, heating at 80 to 150 ° C. for several tens of minutes to several hours causes allophanate crosslinking and / or burette crosslinking, whereby a crosslinked film can be obtained.

Various film forming methods can be used for manufacturing a balloon using an elastic material, but a dipping molding method is generally preferable. In the dipping molding method, an elastic material and various additives as required are dissolved in an organic solvent to form a solution, and a mold is dipped in this solution to form a film. The mold is dipped in the solution to apply the solution to the surface of the mold, and the solvent is evaporated to form a film on the surface of the mold. By repeating the dipping and drying, a film (film) having a desired thickness can be laminated. When the elastic material is natural rubber or crosslinked polyurethane, it is vulcanized or crosslinked after film formation.

The elastic material film forming the balloon of the present invention has a 500% modulus of 28 to 50 kg / cm ^2.
It is necessary to be in the range of, preferably 30 to 45
It is kg / cm ² . If it is less than 28 kg / cm ² , the outer diameter of the produced balloon becomes relatively large by feeding a fixed amount of air, but the shape is likely to be biased. The upper limit of the 500% modulus is that the balloon can cover the distal end of the catheter at the time of expansion, the size of the balloon shape required at the time of expansion can be secured, that is, it does not become difficult to expand. 50 kg / cm ² or less, preferably up to about 45 kg / cm ² .

In the present invention, the value of 500% modulus is measured by a tensile tester (manufactured by TOYO BALDWIN Co. LTD) according to JIS K-6301.
Crosshead speed 500 mm / min, temperature 23 ° C, humidity 6
It is a value calculated and measured under the condition of 5%.

The balloon in the catheter of the present invention has a bias occurrence rate of 10 measured by the measuring method described later.
The following is preferable. The balloon in the catheter of the present invention is preferably made of a material having a permanent strain (measurement method will be described later) of 20% or less in order to prevent the occurrence of slack. If the permanent strain exceeds 20%, slack is likely to occur when the balloon is deflated, and when left in the blood vessel, blood is retained near the slack of the balloon, resulting in a rapid increase in thrombus generation rate. It is estimated that

500% of the film made of elastic material
To obtain a modulus of 28 kg / cm ² or more, for example, in the case of using natural rubber, a method of appropriately selecting the compounding prescription such as changing the type and addition amount of the vulcanizing agent, and in the case of silicone rubber or polyurethane, Is a method of adjusting the constituent components and molecular weight, and is not particularly limited. Also,
In order to obtain a film having a permanent set of 20% or less, the crosslinked polyurethane as described above is preferable.

[0027]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

The methods for measuring the physical properties are as follows. <500% Modulus> Obtained by a tensile tester. The measurement conditions were measured and calculated according to the following method according to JIS K-6301. Tensile tester: TOYO BALDWIN Co. LTD
Company temperature: 23 ° C Humidity: 65% Crosshead speed: 500 mm / min

<Permanent Strain> A sample pressed to a thickness of 2 mm was punched out into a No. 3 type dumbbell (JIS K-6301) and stretched and shrunk up to 500% repeatedly between the marked 2 cm rating lines for 10 minutes. After holding
After removing the force and leaving it for 10 minutes, the length between evaluation lines was measured to measure the residual permanent strain. Permanent strain is
It was expressed as a ratio (%) of the elongation to the original length (2 cm).

<Measurement of outer diameter of balloon shape> A balloon attached to the catheter tube is filled with a predetermined amount of air (0.8 c).
c) is injected and a laser outer diameter measuring device (manufactured by Keyence Corporation,
The balloon shape was measured by LS-3100).
The maximum value of the measured balloon outer diameter was defined as the balloon outer diameter.

<Balloon shape deviation and deviation occurrence rate> FIG.
As shown in FIG. 2, the outer diameter of the balloon was divided into lengths a and b from the center line of the distal end of the catheter, and the ratio was taken as the degree of deviation, and the average of all the numbers measured in each sample was shown. Further, from the viewpoint of the presence or absence of the exposure of the distal end of the catheter and the appearance, the deviation degree of 1.8 or more was regarded as the deviation occurrence, and the deviation occurrence rate in each sample was displayed as the deviation occurrence rate. The total number of samples was 100.

<Measurement of degree of exposure of catheter distal end> In the intravascular indwelling catheter, if the distal end is exposed when the balloon is expanded, the heart and the inner wall of the blood vessel may be damaged, and the distal end may be damaged. Since there is a risk of arrhythmia due to stimulation of the inner wall of the heart by the portion, it is desirable that the distal end portion is exposed to 2 mm or less, preferably 1 mm or less, more preferably no exposure. Therefore, the length of the distal end portion of the catheter exposed from the expanded balloon was measured and displayed as an average value of all numbers. The total number of samples was 100.

<Ragging Occurrence Rate> The balloon was inflated and then deflated, and the shape at that time was visually determined, and when the occurrence of slackness was clearly observed, the occurrence of slackness was evaluated.
Then, with respect to 100 samples, the number of occurrences of slack was determined and the occurrence rate (%) was obtained.

<Antithrombotic property> The antithrombotic property of the balloon was evaluated according to the following three grades. : Thrombus does not occur even if blood flow in the balloon for 30 minutes or more. Δ: A thrombus was partially observed from around 30 minutes. X: A thrombus was formed by 30 minutes.

Examples 1 to 4 and Comparative Example 1 Natural rubber latex was added to potassium hydroxide solution, potassium laurate solution, sulfur dispersion as a vulcanizing agent, zinc oxide dispersion, and dibutyldithiocarbamine as a vulcanization accelerator. Five types were prepared by adding a zinc oxide dispersion and varying the amount of the vulcanizing agent, and each of them was used as an elastic material to form a film by a dipping molding method, followed by vulcanization to a thickness of 0. A 2 mm natural rubber balloon material (membrane) was prepared. A 500% modulus was measured for each balloon material thus obtained. Next, each balloon material cut into a length of 6.0 mm was attached to the distal end of a polyurethane catheter tube having an outer diameter of 1.6 mm by a known method,
The balloon portion and the pacing catheter tip were made. The number of prepared samples was 100, and the balloon outer diameter, deviation, deviation occurrence rate, and distal end exposure were measured. The results are shown in Table 1.

[0036]

[Table 1]

As is apparent from Table 1, when the conventional balloon material having a low modulus of 500% is used (Comparative Example 1), the degree of deviation and the occurrence rate of deviation are extremely high. In contrast, the balloon material has a 500% modulus of 28-
It can be seen that in the case of 50 kg / cm ² , the deviation of the balloon shape upon expansion is significantly reduced.

[Examples 5 to 8 and Comparative Examples 2 to 4] Using each material shown in Table 2, a film thickness of 0.
A 2 mm balloon was prepared and evaluated.

In Table 2, each material and the crosslinking (curing) conditions are as follows. (1) PU (a): Toluene diisocyanate-polytetramethylene glycol prepolymer (manufactured by Uniroyal Co., L-42) 100 parts by weight, and methylenedianiline curing agent (Uniroyal Co., Ltd., Keicher 21) 10 parts by weight. It is a two-component curing type polyurethane with the addition of
It was cross-linked by heating at 85 ° C. for 1 hour. (2) PU (b): Polyether type millable polyurethane (manufactured by Uniroyal Co., Adiprene E, molecular weight 2-3)
10) 100 parts by weight of dicumyl peroxide was added to 0.3 parts by weight. After film formation, the film was heated at 160 ° C. for 30 minutes for crosslinking. (3) PU (c): Moisture-curable polyurethane (Olestar M54-80A, manufactured by Mitsui Toatsu Chemicals, Inc.), which was left in the room for 1 week to cure after film formation.

(4) PU (d): 4,4'-diphenylmethane diisocyanate (MDI) (manufactured by Nippon Polyurethane Co., Millionate MT) in 100 parts by weight of a polyester polyol (manufactured by Nippon Polyurethane Co., Ltd., Nipporan 5018, viscosity 470-620). ) A two-component polyurethane containing 10 parts by weight and the like, which was heated at 100 ° C. for 2 hours and cured after film formation. (5) PU (e): MD with respect to 100 parts by weight of thermoplastic polyurethane (Peresene 80AE manufactured by Dow Chemical Co.)
A film was formed from a solution containing 3 parts by weight of I and heated at 180 ° C. for 1 hour to crosslink. (6) Thermoplastic PU: Dow Chemical Co. (Peresen 80
It is a thermoplastic polyurethane of AE). (7) Vulcanized NBR: Acrylonitrile-butadiene copolymer rubber having an acrylonitrile content of 45%, which was vulcanized after film formation. The results are shown in Table 2.

[0041]

[Table 2]

[0042]

According to the present invention, there is provided a catheter with a balloon, in which the deviation of the balloon shape is significantly prevented, the occurrence of slack is suppressed, and the functionality is excellent. The catheter of the present invention is suitable as various balloon catheters because its balloon portion can exert its function without problems.

[Brief description of drawings]

FIG. 1 is a front view showing a non-biased balloon shape after expansion.

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

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

[Explanation of symbols]

1 Catheter distal end 2 Balloon 3 Catheter with balloon a Length of the longest part from the catheter centerline to the balloon outer diameter b Length of the shortest part from the catheter centerline to the balloon outer diameter

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Hiroshi Hisaki 4-25-7 Shotori Takatori, Yokosuka City, Kanagawa Prefecture (72) Inventor Katsu Okawa 17-13 Shinohara Nishimachi, Kohoku Ward, Yokohama City, Kanagawa Prefecture

Claims (5)

[Claims] 1. A catheter with a medical balloon, wherein the balloon is made of an elastic material and is made of a film having a 500% modulus in the range of 28 to 50 kg / cm ² . 2. The catheter according to claim 1, wherein the elastic material is at least one selected from the group consisting of silicone rubber, polyurethane and natural rubber. 3. The catheter according to claim 2, wherein the film is a crosslinked polyurethane film obtained by forming polyurethane into a predetermined shape and then crosslinking the film. 4. The catheter according to claim 1, wherein the elastic material has a permanent set of 20% or less. 5. The catheter according to claim 1, wherein the elastic material has an excellent antithrombotic property.